Personally, I've never noticed. They do recognize and respond to sounds that we make and can even sense the tone of our voices. They know when we're mad, happy, etc....So to me, it's plausible that dogs respond to music and can sense the "tone" of a song as well.
But I'll tell ya, if my dog ever responds more positively to Brittany Spears than The Rolling Stones......someone's going to the dog pound.