The BlackBerry is the phone for you according to what you just said. Here's some good stuff about it:
Facebook App - lets you take pictures and upload them to your mobile uploads seemlessly (you don't even have to open the App)
MSN Messenger, Google Talk, Yahoo! Messenger, etc. - there's a blackberry app for all of them. and if not, there's meebo. it runs int he background so it's always on unlike the iphone.
BlackBerry Messenger - instant message to any other blackberry, send photos and voicenotes, all part of the internet package.
Surf the web with either the BlackBerry browser or install Opera Mini, which is a great way to surf the web (not as great as the iPhone, but it's good enough).
Calling quality is great. SMS is just as great as any other phone. MMS, e-mail, and everything works seemlessly.
I say get one. Don't get a pearl though. You'll hate the keyboard forever.