I have read in a couple places that the Camera in the Thunderbolt is better than the one in the Incredible, Evo, and Inspire. Haven't seen this officially, but it's supposed to do better with low-light and motion.
Checking out some threads where folks posted pictures with the above HTC phones -- I think the TB's camera will be pretty sweet. Anything in day- or bright- light looked great. Very clear, vivid colors, etc. Low light will probably be not so great and the double LED flash might actually kind of wash out a subject you're close to. I've read it also sometimes puts a yellow tint on the shots.
Anyway, here's a youtube vid where they open the camera app and mess with it for a few seconds. It launches FAST. The auto-focus looks pretty cool. Also, watch this in 1080, the quality is really stellar and you can see how good the screen looks!
http://www.youtube.com/watch?v=LS6zBtFA370