Hey, now, Reap, all us yong 'uns ain't too bad.
I'm 21, and the closest to evil I've ever played is a neutral kobold who is self-interested and self-important, but who also won't go out of his way to hurt, wound, or injure people who he's supposed to be working with...he wants to prove his power, rule the world, etc., but he's not going to be an ass about it.
I'm more often DM, so I guess I play evil a lot, actually...
My players generally don't go in for evil alignments. There was once, when it was more of a new thing...("Dude! He's letting us play evil!"), but it was done thoughtfully, and with skill, and I *still* made them save the world by making it a quest of self-interest, that they were willing and able to go out of their way to hurt and kill people in their quest. And many of them died at the hands of constubalry.
You could solve the problem perhaps easily...your players probably feel confined by the alignment system, like it can't represent what they truly want to do....
So tell them "Act however you want...you don't have to pick an alignment"
And then pick an alignment for them based on their actions. Do they flout any and all authority they come accross? Chaotic. Do they go out of their way to kill babies, or are they content in only killing the babies who try to kill them (Evil in the first case, Neutral in the second)...or would they go out of their way to find what's causing the killer baby rampage in the firs place? (Good).
You keep track of alignment. Tell the players that. They don't need to label themselves anymore -- you just label how they act.