It's interesting to me that this discussion went from "do you listen to christian music?" which I interpret as bands that specifically classify their genre as "christian" to "what "is" christian music?"
I think the OP wanted to know if you listen to bands that are on christian labels and classify themselves as a christian band. Not as in that's what the member's religion is, rather that's what all of their songs are about.
It is interesting that so many bands that don't have that classification have religious songs (someone showed some good examples above).
Hell, Black Sabbath made Christian songs.
It's also very interesting to me that news of Christian bands has come up as them
not really being Christian (not that there's anything wrong with that). Which to me is very uncool. As a friend of mine put it "they're using God to sell music" which is very shady. it's kind of like Dennis Leary selling me a Ford F150 only to find out he's adamantly opposed to trucks and will only drive mopeds.