My issue with deleting Facebook is that a lot of services depend on it for authentication and friend/contact discovery. I wish there were an open standard for a social graph.
So I'm confused as to why this is a necessity. What services do you use that won't function without your Facebook account?
As for authentication, thankfully most sites let you register an account with them. It's a little inconvenient, but with a password manager it's simple. Still, I wish OpenID was more widespread.