Just to preference this I am pretty new to 3rd edition and have only run as a player in 2-3 sessions and one improntu as a DM (I however have more than 6 years experience as a 2nd edition DM).
Well anyway I am going to Buy Savage Species and maybe the Player's guide to the Planes soon. I want to know what you think would be a good idea in terms of limiting charcter creation. The only 2 players I have so far are very new to roleplaying in general but more experienced players are likly to get involved. What are your thoughts?
I'd personally limit it based on what you had in mind for your game. Get a grip on the game idea and derive your restrictions from that - there's no reason to shoehorn a character into the plot when you could have just said from the beginning "Please don't play an X..."
I'd use the following questions to make my decision:
1) How high a level will the game be? (aka, no celestials at level 1)
2) What bad guys will be involved? (aka, if a player wouldn't fight the bad guys due to race - take that into account)
3) Are your players experienced in the planes or not? (If not - primes may be better choices for them to play before they learn the setting.)
4) Account for modes of travel. An all winged party will handle things differently than quad or bipedal. (Same goes for special abilities.)
and last but not least
5) Account for inter party incompatibility. Githyanki + githzeri = BAD.
If you're looking for completely generic advice? #3 is your most valuable one. If the players are new to RP, keep them with something humanoid unless they're really picking it up quickly. If new to the planes - keep them mortal for the same reason. The gith races would probably be the furthest out I'd get for new players - simply because there's so much background to the species it may be overwhelming.