(Apologies in advance for a post telling you about my character, but that isn’t my main goal here! You’ll see.)
At tonight’s D&D game, I’m playing my 7th level drow thief, Rylatar. He’s a Dex/Cha based (Int dump stat) character, a dandy from his city (Erelhei Cinlu) who never really cared about learning or politics. He spent all his time in classes at the wizard academy and temple of Lolth fantasizing about his teachers and fellow students (and in some cases, acting on these fantasies). He finally left the city as part of a particularly disturbing scandal that involved his lover becoming his mother and attempting to eat him. (It’s complicated!)
He fled to the surface and took up with a new set of friends (the other PCs), some of whom he likes/flirts-with/actively helps in combat, some of whom he loathes/mocks/snickers-at-when-they-fall-in-battle. But he always goes out of his way to help his friends in need, no matter how messed up their relationship is. He has a ridiculous accent, which is a little bit French, a little bit Spanish, and a little bit Cajun. His 4th-wall busting reply to most question is “Ah, dat depends. What be your Insight score, no?”
And did I mention? He’s evil aligned.
No “chaotic good rebel against his evil race” for Rylatar. He’s a drow. He thinks like a drow, reacts like a drow, and is busy building a criminal empire between adventures in the campaign.
And where I’m going with his character is, I think, a good place for evil PCs. He has his own motivations (mostly, they’re golden), he’s greedy, sneaky, acerbic, but at the same time loyal to the group. They’ve all saved his life several times, and they’ve stood with him through thick-and-thin. Even when betraying them is easier than the converse, he’ll stand up with his fellows and fight it out. And it isn’t just because the other PCs are valuable to him, but because he honestly likes them and appreciates their needs and desires as well.
And who knows? Maybe their inherent goodness will rub off on him.
An evil character is not out to get everyone he can all the time. He may have exceptions to his evil ways–people he values and even loves, who might even be the reason for his ruthless behavior. When playing an evil PC, you’re likely to make the game better and get a better roleplaying experience by testing your character with these sort of relationships. Put him into situations where he will have to choose between friends and himself, where he sees two paths (the easy one and the hard one) and has to decide. And make the movement toward a good alignment one of the overarching stories: if the other PCs are good, they should be thinking about helping you redeem yourself, rather than just mistrusting you.
Oh, and when you see your six-armed drow priestess sister, who’s been hunting you to restore the honor of your house . . . shoot her in the face with your crossbow. 
Cheers
