Interestingly enough, even though I don't value Facebook much, it's the only one that would be hard to replace: Google could be replaced with Bing or DuckDuckGo, iPhone with Android, but where will I keep track of all my Facebook friends?

Well: the ones I really care about are either (a) in my contacts, (b) hacker types that have Google+ (I presume "Google" includes all google services.), or (c) I have their e-mail.

Now, I would lose touch with a lot of people BUT I would still hear all the important things through word of mouth.

I find that I don't honestly use FB to stay in touch. I use it as a glorified soapbox / timewaster.

I know that I could live w/o Facebook because days go by where I don't check it at all. (I haven't really looked at it since Diablo 3 came out, for example. Then again, I haven't talked to my IRL friends either.)

Not a day goes by that I don't have to use a Google service (they're my email provider, for starters. also as a programmer Google is kind of a necessity.)

And my iPhone? Well. I feel kind of naked if I don't have it.(or it isn't charged.) There's a really weird helplessness that comes with being unable to call for help at any given moment in time.

myspace

Facebook would be the first one, of course. And iPhones don't interest me anymore.

If for some reason I had to make this choice? Facebook. I wouldn't even blink.

Gave up google months ago, haven't missed it.

Google Search, or Google [Books, Docs, YouTube, Google+, Answers, GMail, etc.]

If the latter, you are far stronger-willed than I, sir!

facebook

Just gave up my iPhone yesterday. Switched to an HTC One X (Dual core 1.5Ghz, Android Ice Cream Sammich, 4.7" screen.. UNREAL).

Buh bye Apple.