I remember quite vividly when AD&D 2e dropped assassins and half-orc when jumping editions. I was upset that TSR had dropped evil classes and races from the realms of PC use. This, after playing in 3 groups in 2 different states and seeing just one evil PC - a half-orc assassin. I really should have been more upset at the filing off of the serial numbers of the demons and devils between editions.
It isn't even like any of those groups had a hard and fast rule against evil PCs - we just used the commons sense rule of "even evil doesn't have to be a dick!"
These days, I'd probably allow an evil PC if he player were able to explain up front how they could play the alignment and NOT be a dick to the rest of the party.
So, do you allow evil PCs? Yes? No? Why? Why not and all that other shit that comes prepackaged with these types of questions ;)