If I'm working on a special project (let's say my webcomic) I have a playlist that I've put together with music that I feel represent the characters and their feelings. It makes it a lot easier to get into the right moodset. I also really like to listen to movie sountracks, lots of great songs with the same feel to them in one place
When I'm inking, however, I really like to listen to my favorite Swedish morning radio show (Morgonpasset) or podcasts.