I'm with the "wait and see" crowd. I've been in groups where everyone was CE/insane and we had a blast for about a month; then the DM told us all to knock it off. There was also a player in college known for creative ways to make others look like asses, or just taking stuff off their corpses. Playing with that group was different, but fun.
The problem isn't having an evil PC, though. I've played my share of evil characters, both with non-evil and evil groups. The trick is to play rational. Evil characters still have self preservation instincts and can follow a chain of consequences. In 3e, I played a ranger/assassin with Quick Draw (or whatever the feat was). I had no compunctions about killing people, innocent or not, but I didn't want to go to the gallows or have some fool paladin hunt me down. When the crazy cultist starts threatening people, including one murder, in a semi-public area, I just said to the DM, "I'm intrigued. I watch her intently to figure things out." Next round, she continued on, so I studied her some more. Same thing, next round. The round after that, I cut her head off (surprise attack after three rounds of study) and then turned it over to the watch. Boom! Instant hero, with a dozen witnesses, and benefit of the doubt in future questionable situations. Also, the rest of the group was a combination of thankful and scared such that I was pretty much the unofficial leader, from then on.
Smart evil = interesting change and challenge.
Dumb evil = annoying and disruptive (unless the whole group is just cutting loose).