Nokia N900: check it out on this video.
It is not only superior to the iPhone 3GS in what you can do -- the user interface is really streamlined.
I have an iPhone. I am not afraid to say this: the N900 smashes it. Here's just a quick example -- in the form of an interaction demo video -- of what the N900 can do:
For a blow-by-blow feature comparison against the 3GS, go here.
Edit: and the promo video is to die for!