I've got the HTC Hero, very happy with it.
Looking to get the HD when my contract runs out, a nice speedy 1Ghz snapdragon processor to keep things running smooth.
Droid its self is very smooth, since i've had mine, coming up to 18months the market has updated three times all free and I've had two large updates to the OS all free. The Droid forum is also very cool if you want to over-clock your handset or do other clever stuff with it.
Three are doing some cracking deals on iPhone 4 at the moment but your on a two year contract with them, only 6 months longer than what i've got now. I normally get very sick of a handset, but this has kept me entertained. I also like that most things on the Droid market are free or at least have a free version available with no time limit.