Music is a big part of the writing process. This is evidenced by the mile long favorite song threads that I find in forums throughout the web wherever writers gather.
Personally, I give each character or situation a theme song. I think it makes things more colorful.
Each night I go to bed with a different song in my head. If you want to see if you can guess what that song is... I'll give you a clue, then watch the video to see if you're right.
Clue: Back when this song was a hit, being a baby momma was not common and it made your child an outcast. This sad but supreme song on my list is about growing up without a daddy.