I could name quite a few openly very famous Christian musicians, but I would struggle in naming non-theist ones? know of any? do atheist musicians make better music?
Would you continue to listen to your favourite band if you found out they had some crazy religious views?
I think: The quality of music does not depend on the artist's religious view as much as the working result of an engineer doesn't depend on his/her religious view. I do watch and like movies starring Tom Cruise though he's holding a rediculous view on the universe. My most favorite music genre is country music and it's almost impossible to avoid religious references in it. I just ignore them or take single words like "god" or "lord" as filling words with no meaning just as "oh" or "yeah".
The music of non-theist musicians like Billy Joel, David Gilmour (Pink Floyd), Mark Knopfler (Dire Straits), Eddie Vedder (Pearl Jam), Björk, or John Lennon [http://en.wikipedia.org/wiki/List_of_atheists_in_music] is neither better nor worse than religous artists. Sometimes one can't even tell the difference.
One great country song is "My Heaven" by Trace Adkins. Though he is certainly not an atheist, this song is atheistic and blasphemous.