I'd say I would be deprived from certain social interactions and some of my friends if I couldn't use it.
If my friends can't be bothered to write a letter, write an email, call, stop by, etc and stop all contact b/c of lack of Facebook then they're not real friends.
I had a FB account back in the day with lots of friends who I rarely interacted with and vice versa. I canceled the account and never heard from them again. It does kinda suck, b/c I considered some of them to be good friends (a few were in my wedding) but when they don't respond to other forms of contact, well, that just shows they don't want to maintain the friendship. Now when I visit the city in which they live I invariably hang out with different friends who put in the effort to return a call, send an email, etc.
IMO if your idea of maintaining a friendship/relationship is an impersonal status update broadcast to 500 people then you're not worth the time.