Facebook is neat and I like having something on there. It makes me feel like I have a bit more connection to my school (given that I live at home instead of dorms) But it hasn't helped get me any new friends, really.
You can restrict your facebook profile so that only your friends can see you, so you can stay pretty private, but still, I wouldn't blame anyone for not having a facebook page. I don't have a myspace for the same privacy reasons.