When pencilling and lettering, I usually don't listen to music. I find that at these moments, that extra bit of concentration is very important, as these first two steps are the "backbone" of the comic. I usually listen to music when inking though. My tastes consist of alt rock, punk, and post-punk. I've found that it's helpful to listen to entire albums at a time — when the album ends, it's a good time to take a stretch break.