I tried to talk myself into downgrading to a dumb phone recently. Did not work.
I'm on my 3rd iPhone (had the 3Gs, 4 and now 5). I love it. I can't live without it.
I'm just busy enough with work & rescue that I want to be able to access my email. I utilize my calendars (I sync to my Google calendar). I would be lost, literally, without GPS. My music, all 10GB, is right there. I can play games and browse the web and the screen is so pretty and bright! I have the Kindle app on my phone, so all of my books are right there as well. (Those also sync, so if I go from my iPhone to my Kindle, I'm on the right page.)
Plus, FaceTime (or skype or whatever) is readily accessible. iMessage. Siri (even though she was being a bit temperamental earlier today).
I also briefly considered a different brand of phone... but I am not a fan of the Android OS. And really, I'm an Apple fan girl and I'm not ashamed to admit it.