Depends on what kind of homework I'm doing. If I'm programming or doing bullwork math, then it can be anything really. Usually something upbeat to keep me going, but it really doesn't matter too much. I find that if I'm problem solving, I can tune out the music just long enough to work it out, then use it as energy to plow through some calculations that don't really require much thought.
If I'm studying, or it requires more thought, then maybe some soft classical (Chopin works fine) or some other obscure quiet stuff that I won't be tempted to sing along to. I've got some cuban music that we had at my old job that works quite nicely.
