I am over 2 years into using my iphone and it has been a pretty great experience. I went from a standard phone to my first ever smart phone and I can't imagine life without it anymore.
It isn't just the email and internet anymore. The app store experience can't really be beat and lately some of the iOS 5 features have really topped it up (free texting internationally with other iPhone users and the iCloud syncs information between my wife's phone and mine).