Whenever I write, I have music playing in the background. The genre depends on what I'm writing and mood of the novel. For Sweet Jazz I compiled a playlist of jazz tunes. While I created a playlist of popular music from the 1950s for my upcoming novel, A Bookie's Odds.
My favorite genre is goth. There is something about songs from The Cure, Gene Loves Jezebel and Lowlife that help relax me or brighten my mood.