Nexus One. Even Tech podcast host Leo Laporte of Twit.tv who has always been an iPhone guy says the N1 blows the iPhone out the water.
The one area that is often quoted for the iPhone is the size of the app store, however studies have shown that after += 3000 it makes no difference how many apps there are because from the 2000th most popular app onwards practically no one actually has them installed - they are irrelevant. What does matter is the range of apps and the iPhone falls behind there because of the hardware and policy restrictions: no multi-tasking so no background apps (and there are some really great apps in this category), Android is ahead in terms of barcode scanning and shopping and augmented reality since Android phones have had auto focus and a compass from the beginning.
Add to that the N1 speech to text recognition, Google Goggles, blazing fast processor, and open platform and the N1 is a clear winner. Even Apple founder Steve Wozniak says the N1 is his favorite gadget!
I don't know when the N1 will be available here though. I'm getting mine from the US