Hello there, I noticed that usually people interested in Planescape have good taste, so I got curious about which other campaign settings are you guys into... you can list it as a top 5 or top 10 if you like...
ps.: not necessarily D&D, and yes, you can include vampires or werewolves in it, don't be shy
From D&D: Ravenloft, Dark Sun, Spelljammer. Sharn, in Eberron. Gloomwrought.
Gamma World, with a special soft spot for the most recent edition and the Alternity and d20 Modern versions. But I love the basic idea of the Big Mistake-- that upon activation, the Large Hadron Collider collapsed all realities into a single, not particularly viable universe.
The Imperium of Man, from Warhammer 40,000 (especially Rogue Trader and Only War). The Culture, from the novels by Iain M Banks. Sufficiently Advanced (http://suffadv.wikidot.com/about-sa) and Diaspora (http://www.vsca.ca/Diaspora/). Cowboy Bebop, Mass Effect, Black Mesa, Farscape, Lexx.
Rokugan, the fantasy feudal Japan from Legend of the Five Rings. Seventh Sea. The Dreaming, London Below, and the market town of Wall. Discworld.
The old World of Darkness, particularly Changeling: The Dreaming and Mage: The Ascension. Wraith: The Oblivion is also pretty cool, but the spot in my heart it would take is already occupied by the Ninth Underworld, from Grim Fandango. I like all the factionalization and politicking of Werewolf and the Masquerade, too, but I realize that they didn't line up with more mainstream expectations for those monsters. More's the pity-- that's exactly what I liked about them.
I just wanted to clarify here, while I did a little bit of brainstorming very early on for Dark Roads and Golden Hells, I wasn't otherwise involved and I didn't have anything in the final product. I had way too much going on at the time and couldn't devote the time needed to that sort of Open Design collaborative effort.
However it's a damn fine book, and several other folks here on Planewalker were also involved in the project, and have sections in the final book. 
For the broader topic here:
I'm wholly enamoured with the Golarion setting for Pathfinder at the moment, and it has gobbled up my creative mojo for the past several years. I've done quite a bit of freelancing for Paizo, heavily but not entirely by any means, on planar stuff for the setting. Heavily, heavily inspired by PS here on the planes. Plus they've had Colin McComb of PS fame work on stuff for them!
Eclipse Phase is a beautiful, horrific setting. Vaguely lovecraftian dark transhuman sci-fi stuff. Also the folks at Post Human are just awesome individuals. I've never played a game, but I've devoured each and every book they've published. Really, truly inspired stuff. I wish I had more time to write, more time to learn the system, and more time to whore myself out to them to get to work on something for EP. 
New World of Darkness (Mage and Changeling in specific). I really like it, and since I never had much exposure to oWoD, I don't have to judge it by comparison. I've played only a very little bit of it, but it's good stuff to read.
Forgotten Realms used to be one of my favorite non-planar settings. Then 4e's Spellplague hit, and honestly the setting is a withered husk of its former self. I haven't much bothered with it for several years, and since they don't appear willing to rollback or retcon anything, I think at this juncture I've moved on.
I'm not very familiar with Golarion, but I agree with everything else you just said, especially for Forgotten Realms.
Mage and Changeling are still good in nWoD. Certainly there's a lot of good ideas that've been further developed, and the system is much improved. But there's just something about the old settings that I like more. Toys I'm not quite ready to put back in the box.
As a whole I don't find any setting as interesting as Planescape. Several settings I've read about have parts that I like, that I find worthy of including into planar adventures.
Golarion - their planes, religions, Azlant, city of Absalom, Numeria, possibly Mwangi
Greyhawk - mostly interested in its ancient history
Mystara - Blackmoor, immortals part
Forgotten Realms - Imaskar and post-Imaskar civilization, includes the Red Wizards and Rashemen
Midgard - their planes, city of Zobeck and Margreve, the western wastes and the Northlands
Bas-Lag - from Dragon #352, for its magical technology, the ancient Ghosthead civilization
Ptolus - chaositech ...
Eberron/Iron Kingdoms - mostly the monsters, the Quori, daelkyr, the undying ...
Ravenloft - unique monsters/npc's - I'm not familiar with the rest of the world
Shemeska, you have no idea how glad I am to hear that somebody of your, erm, stature is a fan of the new world of darkness. I feel like every time I tell somebody I like the setting, I have to begin by apologizing for myself in order to avoid provoking a rant. I spent a lot of time running Masquerade and, to a lesser extent, Apocalypse and Orpheus, and I must admit that the newer setting just inspires me in ways that the old one never did.
Anyway, I better stop myself before I start ranting like the brazen hypocrite that I am. 
I'm also a big fan of Golarion; I can't put my finger on why, exactly, but it's one of the few settings that just fires my imagination. It also managed to get me to fall deeply in love with halflings, a race I hadn't ever given much thought to in 15+ years of gaming. Also, the serpentfolk make me happy, and WOTC can keep their yuan-ti and mind flayers, for all I care. :}--<
Of the TSR D&D settings, the only one I really warmed up to (other than Planescape, of course) was Cerilia, the continent where Birthright takes place. How can you not like a setting that practically begins with the words "there came a time when the old gods died"? I thought they did a really good job of giving a lot of the petty dominions distinct "personalities," and found the way blooded regents interacted with their realms pretty interesting (though I'm not sure they all needed to get random super powers, as well). Also, they did a good job of making Cerilian elves seem a little bit alien, what with them being the only race that can innately cast arcane magic, their lack of religion, and the fact that they're literally incapable of having a lawful alignment.
I got really into the Exalted setting for a while; I can hold forth for hours on the history and anthropology of Creation (and have, much to the chagrin of my gaming buddies). That said, as crazy a kitchen sink as Exalted is, there was always a fair amount of stuff that I didn't like about the setting, and I feel like the whole thing has soured on me over time. Honestly, though, I might just be turned off by the memory of years of frustration with the Exalted system.
This one might be a little obscure, but I grew up reading Joe Dever's Lone Wolf books, and I still have a soft spot for Magnamund, the world it takes place in. For me, it sort of informs my baseline assumptions about medieval fantasy in general. It's a little bit gritter than Forgotten Realms or Eberron or what have you, though part of that comes from Gary Chalk's illustrations, in which everything looks sort of dirty and run down (especially the people). Also, it's the kind of setting in which, no matter how awesome you are, overcoming the forces of evil is a struggle, and all that separates the mightiest heroes from an untimely death is one bad decision.
Talislanta. Inspired by Atlantis and Jack Vance's Dying Earth series, it's a decadent, high-magic world with flying ships empowered by the distillation of dreams and dozens of colorful races, none of them exactly human and none of them elves. You can legally get the complete library of this setting for free at Talislanta.com. From a planar perspective, I especially recommend The Midnight Realm/The Darkness (essentially the same book, for different editions of the game), a continent where the various inhabitants of the Lower Planes mingle and trade. There's more detail on the Talislantan cosmology in the Codex Magicus. Some of it was published for the d20 system.
Tékumel. The official website is Tekumel.com. It's an extrasolar world terraformed in the far future by humans of Central American and Indian descent and populated by many alien races before a cataclysm destroyed civilization and pulled it into another dimension where magic and gods are real and very present. (Takes a deep breath). Complicated backstory aside, it's a very interesting, refreshingly different setting with fully fleshed-out races and cultures completely unlike those of any other fantasy world (and not obviously like that of any science fiction world either). The gods are divided into pantheons of law and chaos and magic draws forces from other planes.
Glorantha, the world of the RuneQuest and HeroQuest RPGs. The glorious part of this setting, more than anything else, is its elaborate mythology. It has planes where heroes can travel to relive and rewrite the myths that made the world.
HōL, or Human Occupied Landfill. And now for something (cough) completely different. HōL is a completely hand-written book (so it reads like someone's sketchbook filled with doodles and jokes, which is what it is) about a planet turned into a landfill and the garbage that lives there. The main book doesn't even contain rules for character creation (they advise you to use a pregenerated PC or reverse-engineer your own character based on those examples) but the sequel, Buttery Wholesomeness, does.
Beyond that? I remain a Greyhawk fan because I'm a D&D fan, and Greyhawk's DNA is found throughout the game. Probably the thematically strongest presentation of the setting was Carl Sargent's dark, demon-haunted From the Ashes and the hell-drenched supplement Ivid the Undying (google the title; someone made a nice-looking PDF out of the unpublished document). After that they back away from the darkness and become a retro-D&D world involving delving in dungeons and fighting slavers and sorcerous monks. It's still a strong setting, which became obvious when it was used in Paizo's first adventure paths in Dungeon Magazine. I don't know if I can honestly call it the best setting, but I've been part of its fandom for so long that I can't look at it objectively. I think - much more than most game worlds - it's a setting that's made to be messed with, to be knocked around and tampered with, reinterpreted and turned into a world of your own.
Golarion is very good, not surprisingly given the talent (the aforementioned Paizo) involved in making it. Its supplements are gorgeous, too, full color with beautiful art. It does what it sets out to do, which is provide space for virtually every kind of medievalesque or pulp fantasy RPG adventure you can think of, from Burroughs-inspired alien worlds to the City of Brass to ancient Egypt to revolutionary France to the soul-devouring daemons of Abaddon to Baba Yaga's hut to Asian-inspired lands with tengu and serpent men to the nightmarish, otherworldly plateau of Leng. It has a focused editorial staff without much turnover, so there isn't decades of contradictory continuity to deal with, and it's all written by contemporary authors with contemporary sensibilities so you don't get some of the hokiness you see in a lot of old RPGs (particularly Greyhawk and Mystara). Its nations and worlds are very much all drawn from either historical or literary inspirations and the designers have very good taste in inspiration and make everything fit together plausibly enough. I think it's light years ahead of what Wizards of the Coast is currently putting out.
Honorable mentions:
Gary Gygax's Epic of Ærth, a parallel Earth where magic rules and the lands of Atlantis, Lemuria, Lyonesse, and Ys never sank.
Skyrealms of Jorune, a lost Earth colony with floating islands and hostile natives who wield strange psychic powers.
Stormbringer/Elric! Chaosium's take on Michael Moorcock's Elric of Melnibone series. I'd say it did Moorcock proud if they'd ever saw fit to pay him royalties.
Nobilis. "The wind told me once that everybody gets to play a game of Nobilis before they die. Maybe it's in their secret dreams. Maybe it's in real life. But everybody gets to experience the world of Nobilis once - to leave behind the dead world where things don't talk to you and nobody k nows the purpose of the world, at least for one night, and see the truth."
Great to see Dark Roads & Golden Hells mentioned here, though I should offer a clarification - while it's written for the Pathfinder RPG (of which Golarion is the flagship setting), the locations within are actually part of the Midgard setting from Kobold Press.
I'll certainly second the recommendations for Golarion - as others have mentioned, it's an excellent meeting of variety and quality. Rip gives a whirlwind tour directly above, and I feel like I'd be remiss not to mention Numeria, land of crashed spaceships and confused androids (somehow this all works). Nearby the Asian-inspired lands is an enormous region modeled on the Indian subcontinent that I would absolutely love to see get some substantive attention in the future. The solar system book is very enjoyable and the planar books are outstanding.
Midgard, for that matter. Based heavily in Eastern European folklore, it's both a dark, highly interesting setting and fantastic testament to the value of building something up bit by bit over a long period of time. This has been Wolfgang Baur's homebrew setting since he was a teenager and in the last 5 years or so Kobold Press (formerly Open Design) has been going to town on it in its intensely collaborative, crowd-source-ish way.
And while my memory may be doing some very selective editing here, I'll go on record as a huge Spelljammer fan.
I really like the Iron Kingdoms setting from Privateerpress these days, its has really rich ingame story and very... realistic (?) relationships between the nations. Geographically its pretty small setting, dealing only with half a continent really but its very complex none the less. I'm not sure about their new rules system (in house, it started as a 3rd edition DnD module), it feels a little too much like the wargame its based on.
I've got several books for the old Dead Lands setting, before the core rules got turned into Savage Worlds. It was my first foray into non fantasy settings and I've never been able to let it go completely. Like it says on the cover of the players guide "Spaghetti western... with meat!".
The old Changeling setting is good too, sadly I've never played it but I've read the core book cover to cover several times.
As a forward note, I like to have the option of sending or allowing players to go anywhere in the universe (well the possibility). That's why I LOVE Planescape because it allows that. While obviously, there are a lot of published settings that have never even been visited by players in my game, I have them somewhere in hardcopy or PDF form and it is known (even if only by me) that they exist in my universe. Whether their ever even mentioned or recognized; I assume that if its been thought of, its somewhere in the multiverse. I will even occasionally introduce NPCs in Sigil from random spots like Hyrule (the world from Legend of Zelda). Its rare, but hey, I am whimsical sometimes.
Sorry, let get back on track... Favorite D&D published settings are: (after Planescape)
Forgotten Realms
Ravenloft
Dark Sun
Spelljammer
Though, I'm not that interested, I also have Dragonlance, Greyhawk, Eberron, the old Mystara settings, Birthright, Kingdoms of Kalamar, Rokugan, and I feel like I'm forgetting something, but hey.
I have to say my absolute favorite campaign setting is my own world of L'Rynn, but I imagine anyone who creates their own world will love it best.
I'm not familiar with settings or campaigns outside of D&D myself. There's to much content from that one game for me to really start branching out. I have been known to adapt worlds or settings from video games, movies, and whatnot. I mean with an infinite prime material plane and universe, they're all possible. I usually don't run full campaigns in them though, but as I said before, I like to throw curveballs when that clueless cutter in the Hive is a Blood Elf from World of Warcraft's Azeroth who stumbled into the Cage like they all do.
D&D:
- Golarion
- Iron Kingdoms
- Eberron
Non-D&D:
- Old World of Darkness
- Eclipse Phase
- Heavygear
Numenera
13th Age
Yes, I come from the future.
Hahaha
Numenera looks super cool, I'm very excited for when I'll be able to take a closer look at it.
I'll put in my two cents with the Amber diceless setting. Multiversal, the PCs can go anywhere, become pretty much everything and/or do anything. They can have an entire world (or even universe) to call their own with a single point spent (though holding onto such a world may prove to be problematic if somebody else sets their sights on the place). Since the only real opposition during the course of a regular game comes from the other PCs (and admittedly, a handful of really powerful NPCs), most of the action ends up political. It's really fun to play if you have a solid group. Plus I adore the "Character creation by auction" approach. It sets up all sorts of instant rivalries.
The downside, of course, lies in the setting's open-endedness. If the PCs can scatter to the four winds, it can be really difficult to wrangle them all back together and working towards common goals. And since you could potentially go from a high-fantasy noblebright to a grim-n-gritty space opera, it can sometimes be jarring during play.
Another possibly setting from the future is the Shadowlands:
http://www.kickstarter.com/projects/shadowlands/the-shadowlands-campaign...
Apparently all the magic is sci-fi based, the gods are AIs, psionics works because nanites connect all minds.
There's also some interesting ideas related to linguistics as well as racial/ethnic tension.
Goldenhawk: an alternate history based on Greyhawk.
Mylan'dia - Tyrranouth: a fantasy as hidden tech setting.
Other than Planescape, I tend to like big, complex "kitchen sink" settings. I think the old Cabal setting for GURPS 3e is amazing, and GURPS 4e's Infinite Worlds setting is pretty cool, although I also like their 'standard fantasy' setting, Banestorm, on the world of Yrth.
Pathfinder's Golarion is developing nicely, with plenty of planar material to which many people on these boards have contributed, especially Shemeska: The Great Beyond, Dark Roads & Golden Hells, et cetera.
I have GMed several campaigns of In Nomine in the GURPS system for many years, although I'm not doing so at the moment.