I am not on Facebook at all, even if it is free because I just haven't seen the need for it. I might develop some apps for it in the future, but that's about it. I'm not on Twitter, Friendfeed or Myspace either...
over their lifetimes on facebook? i'd bet that facebook could easily get a substantial fraction of its users to pay that much every two years or so; whether they want to go that route is up for debate.
