As a writer, music is very important to me. There's just something about the way music can affect you and influence the mood and tempo of your writing. When I need to write a tough scene, I usually try to find something melancholy that speaks to me. If I'm doing a scene that is more action-oriented, I blast club and dance music with a fast beat.
The best tool in my music toolbox is Spotify. It's amazing. I have dozens of playlists from classical to 90's hits to my morose mix (my favorite moody, broody songs!). Here are some of my favorite playlists from my WIP:
In Other Words - Ben Kweller
The Freshmen - The Verve Pipe
The Shining - Badly Drawn Boy
Transatlanticism - Death Cab for Cutie
Title and Registration - Death Cab for Cutie
Falling Slowly - Glen Hansard
Mad World - Gary Jules
Pink Bullets - The Shins
Slow - Grouplove
Orange Sky - Alexi Murdoch
The Scientist - Willie Nelson
Heavy In Your Arms - Florence + The Machine
If I'm in the groove and just need music to be playing in the background, I go to my classical mix of Debussy, Chopin, Tchaikovsky, and Beethoven. What does everyone else listen to?