Fluctuates between 30 - 40. 80% are long distance good friends or family that are just quicker to deal with that way, 15% are friends of friends, etc..... that I find cool, but not cool enough to share lots of personal info with. 5% or so are public figures, etc......
I could probably add a pile more, but I keep it around that number because it's easy to deal with. I always wind up feeling bad when I miss some major event in a person's life that they've updated via facebook, it would be worse with a ton more friends.