This Christmas, it looks like Android phones (collectiviely) will be the big sellers. In fact, some analyst reports predict that Android phones will outsell iPhones and Blackberrys by 2012.
There are some differences between the handsets on which Android is offered, though.

I've been using three, in particular, over the last few months. They are the HTC Desire, the Sony Ericsson Xperia X10 and the Samsung Galaxy S. So which would I recommend? Overall, it's a toss-up between the Galaxy S and the Desire, with the X10 lagging on the latest version of Android and not quite as smooth on the touchscreen (although it has, by far, the best camera).
Here's my scorecard for each phone.
Screen
X10 -- 4.0 inches; bright
Desire -- 3.7; decent, but poor outdoors
Galaxy S -- 4.0, best of the three, super-Amoled
Android version
X10 -- 1.6, oldest; soon upgradeable to 2.1
Desire -- 2.1, soon upgradeable to 2.2 (Froyo) on unlocked phones
Galaxy S -- 2.1, soon to be upgradeable to 2.2 (Froyo) on unlocked phones
Camera
X10 -- 8MP; very good; also has its own dedicated camera button
Desire -- 5MP; average
Galaxy S -- 5MP; average; but only one of three to have second, front-facing camera. Also, HD-recording.
Battery life
X10 -- 1 day
Desire -- 1 day
Galaxy S -- 1 day
Design
X10 -- has its own dedicated camera button; nice feel, but edges
Desire -- nice curves, nice materials; practical rubberised back casing
Galaxy S -- glassy
Touch
X10 -- average; not as smooth as rivals
Desire -- very good, iPhone quality
Galaxy S -- very good, iPhone quality
Memory
X10 -- 8GB
Desire -- 8GB
Galaxy S -- 8GB
Price/availability
X10 -- from free on O2 billpay
Desire -- €120 on Vodafone billpay or from €40 on Meteor billpay
Galaxy S -- from free on 3 Ireland billpay