I have sprint and basically my 3 choices are the Palm Pre running WebOS, Samsung Moment with Android, or the HTC Hero with Android.
The HTC has a virtual keyboard so eff that so between the Samsung Moment and the Palm Pre.
WebOS is a solid system and rocks pretty hardcore from what I have used of it on my step-mom and my girlfriends phones but Android is open source and seems to have the potential to have a lot more free apps out there.
