Well, I didn't compare them all, just went for the Droid X based on reviews I'd read and knowing it was big .. e.g. a bit more bulky to carry, but to be honest not much more than the iPhone 3G I carry for work (so now I carry two big phones
).
I love love love my Droid X and have been using it a lot for ebook reading on my early morning walks. It's wonderful for that. as well as everything else it does, mp3 player, video player, phone, browser, etc etc etc.
Love it! It was $200 with a two year contract commitment.
The biggest sticker shock for me was the more than doubling of my monthly service fee from about $45 - $95 or so. I dropped DirecTV though ($47/mo) which makes up for it.
My son has the HTC Hero (but has had a few issues with it after the upgrade to Android 2.2) my other son has the original Google Phone (not sure of the model).