To aid in discussions elsewhere; I believe it is necessary to define the alignments of DnD. These are my interpretations of the binary system; everyone feel free to argue against it and offer their intepretations.
Good is defined as helping others and otherwise seeing to and ensuring the well-being of others. Mixed with this is the willingness to make personal sacrifices (whether of time, money, energy, or blood) for the sake of others.
Evil is defined as hurting others and the disregard for the well-being of others. Mixed with this is the willingness to sacrifice others to yourself (by manipulating them, cheating them, stealing, or murdering).
Law is defined as restricting your behavior within a defined external code of conduct, prefering general order and well-defined boundaries, serving or being part of something greater than yourself, being logical and methodical in ones actions, and willingness to conform and be part of a group.
Chaos is defined as being impulsive and emotional in one's actions, not confining oneself to a code of conduct and rebelling against attempts to be so confined, individualism, refusal to conform, and willingness to leave things undefined.
Ahh... but what do you call somebody who will do or sacrifice anything for their family and friends, showing genuine altruism for their children and parents and spouse, but disregards people outside of their social circle? Do "good" and "evil" cancel out to make that person Neutral?
What about somebody who values individuality and independance, but also society and community? Would that be ethically Neutral?