I have "deleted" my facebook I think 2 times already and always come back because of business. I am thinking about doing it for the third time, maybe 3 is the charm :)
I do have a lot of friends and family there but I think that it made all off us, including me, more anti-social. We see and read everything about people there and see them less and less. If you think about it, there is nothing that we would actually lose by leaving it but there is much to gain. If I am being completely honest, I have not logged to facebook for over a month now and I am still alive and kicking :D Did not notice that anything went wrong with my life.