I listen to the hum of my computer's fans.
Same here. I don't like listening to music when I'm coding or doing anything else that needs massive concentration, or I put the TV on without any sound and listen for that ultra-sound it makes. So in short, I don't listen to anything has a beat while I'm coding.
But when I need to chill a little I mostly listen to all branches of house music, some rap/hip-hop, drum'n'bass... I listen to anything that I find pleasant to my ears