I would use an Iphone but I use Tmobile... but it'll be a struggle to keep up with the unlocking/firmware blocking process..
Step 1: Unlock.
Step 2: Don't install new firmware.
Step 3: Go back to Step 2.
I guess.. but you don't get the full benefits of it.. like the new features with each Firmware.. also one thing that bugs me is that you can't use your own mp3s for ringtones.
You have to pay to have them coverted to the phone?