I think atheists are much more broad in their musical tastes. An example is fundy Christians take to listening to christian music only regardless of how good or bad the music is. Atheists however wouldn't take to just listening to Atheist rock, we are a lot more diverse.
I actually like some songs that are apparently from "christian rock" groups. I guess either the religious message isn't very clear or i just choose to not hear it. Or I just plain don't care.. ya that one's most likely...
There was a great concert by Negativland. Check out the first 2 parts:
I don't know where to find the rest of the concert, but I heard the whole thing on my local community radio station. It was awesome!
Atheist rock from XTC: