I love my iphone. I've had 4 different BB models before but the iphone wins, hands down.

I run my own virtual server for webhosting and I can use my iphone to administer the server. I'm about to move sites over to Wordpress which is easy enough to administer thanks to the iphone app. I love the functionality, productivity and GUI on the thing. Sometimes the iphone has been quicker at picking up mail, facebook updates, twitter updates etc than the laptop.

Syncing it with my mac is seemless.

I've only had my 3GS for a few months and am already thinking of upgrading to a 4.