Actually, my friends and I play BSG, and the similarities are what drew me to this game. I would play Werewolf over BSG if only because I don't have the unpack/setup/teardown/pack time we have with BSG.
If you want little setup, Bang! is pretty good. Setup is like setting up a poker game. Betting on it makes it even more interesting.
My friends and I play The Resistance (http://boardgamegeek.com/boardgame/41114/the-resistance), which is along the same lines, with some traitors secretly mixed into the rest of the group. The difference is, unlike in Werewolf (or Mafia), nobody gets eliminated, so nobody has to sit out for virtually the entire game.
I played this game as an intern at Microsoft in the summer of 2006 and subsequently introduced it to many students in the computer engineering department at the University of Florida. It makes for an interesting study in group psych if you can find people who are tolerant of how unfair it can sometimes be.