I really need to listen to music when I'm painting. If I don't, my mind tends to wander and I quickly lose momentum. If I have music on, I can paint easily for hours.
I find that the style of music that I listen to really helps shape the direction of a piece. I may listen to Nick Cave for jangly frenetic pacing, or I might listen Glenn Gould for minute brushstrokes that require precision. It really varies.
When I find my sweet spot in a painting, I have a tendency to play the same music over and over. If it is capturing the mood of the painting, I don't want to disrupt it. I have literally listened to the same song over and over again for one sitting because it was helping me through a patch on the canvas. That sounds so weird, but that is why I like headphones. No one has to endure it but me!
Some favorites that have taken me through many paintings are Sufjan Stevens, Belle and Sebastian, Anonymous Four, The Smiths, Henryk Gorecki... there are so many more.