I just switched myself a couple of weeks ago. I had been using a HTC Wizard (yeah, I know) for eons and it was at the point where every time I tried to use it I wanted to smash it against the wall.
I too had been resisting the urge and peer pressure to get an iPhone, but after 5 minutes of using it, I knew what all the hype was about. This phone is an amazing device and puts every Windows device I've seen to shame. Fast, intuitive, no hanging or crashing, it just plain works, and works well.
I also love the fact that you can search, download & install just about any app in a matter of minutes (usually seconds) without even having to hook up to a PC, and they DO have an app for just about everything. The one I'm considering right now is Rev, which with the addition of a wireless OBD-II device you can jack into your car from the phone, view/reset any engine codes, and check just about every available stat on your vehicle.
The MS Exchange synching works flawlessly as well. I never could get it working 100% on my Wizard.
So if you're on the fence about getting an iPhone, come on over to the dark side. It's ok to drink the Kool Aid sometimes