I'd also like to point out that evil people need friends too. Adventurers, living outside the moral ken of common folk, are probably good candidates. They may, when the chips come down, betray those friends... but then again, they may not. Just as good folk are over come by their baser nature, sometimes evil folk are over come by their higher nature.
I tend to think the alignment system is pretty crocked myself - hence my penchant for Neutral alignments. Good and evil, law and chaos, all come down - with intelligent creatures - to a series of personal choices. People make choices every time they do something or continue to do something or don't do something. When choice becomes habit, it becomes nature. Thinking people have to think to continue to make the choices they believe in. So alignment, in this regard then, is more a coalescence of the choices behind a character than a map for the decisions to follow.
I think the alignment system should either be much more dynamic and integrated into the game mechanics or dropped all together. But this isn't really a discussion for LEW.
Evil characters, I'm fine with them. In good parties. Fine. There is a meta-game-respect for The Party that all players should have - part of the ettiquette of gaming - in addition to a respect for the in character drama that makes role playing games so interesting.