Personally, I don't think we need anything more than food, clothing and shelter. That said, there are things we darn sure don't want to live without, like a cell phone, a working car, internet, email, electricity in general, etc.
I have one, but I don't think we need it. Honestly, I only use it to chat and catch up with my friends and family anyway.
I'm in my 20's right now, so nearly everyone I know is getting in and/or out of relationships, engagements, and marriages left and right. If anything, I need to check Facebook to keep up on that front, cause I'm almost always the last one to know those things, and I have a terrible tendency to put my foot in my mouth because of it. But it's also a nice and easy way to hear when someone got a job and things like that.
Not having a Facebook or another social media account may make your social life a tad more difficult, because we just don't communicate with others like we did even 10 years ago (which is a shame, IMO). At the same time, it'll probably free up your life and give you an incentive to have close, offline relationships. It's a trade-off, really. If my field didn't basically require it, I'd seriously consider deleting it myself.