Music first. I definitely prefer to listen to good music that suits my mood than a demo disc that has great sound but not-so-great music. Fortunately, I own some discs that have both, but the combination is unfortunately rare. The good recordings are helpful for selecting gear, especially if I'm familiar with them, but I an enjoy lesser recordings as much or more if the music is great.
Music first or sound first?
I just thought it might be interesting to take a poll of those that put sound first and those that claim they put music first in listening to their rigs.