The company I work for does its fair share of mobile development and so we have a bunch of smartphones around the office for testing purposes, and after using all of them several times I still much, much prefer the iPhone (although the Windows 7 phone is kinda nice too apart from its IE7 browser). It does depend on which Android phone you buy however, as certain models are far superior to others, but on the whole it just feels like everything on the iPhone is so well thought out, it all works so well, everything is just so slick. It does suck that it’s only available with 3G at the moment though, not so speedy loading webpages on the go. I have friends/family who have decent android devices, and they love them, until I let them play on my iPhone.
Just my 2 cents!