However, sometimes I found myself craving music when trying to get settled into a grove. At first I thought that it was only mood, but then I realized that it was more than that.
My brain needs the music sometimes to provide a distraction for me when I'm not settled into the deep kind of concentration that precludes any distractions at all. The music is enough distraction, and the right kind of distraction, that I can stay focused on the creative task at hand and not go haring after IRC, or that post I saw two minutes ago, or any of the other things that try to steal the bits of my attention when I'm trying to focus.
Music with a good solid structure is the best. I can't listen to unstructured music when I'm trying to sleep, and when I'm trying to concentrate, if I don't know the music or if I can't predict the structures of the song to some degree, it will distract me more than I plan to be distracted. Baroque is good. Things with the structure stretched out too far are bad. Techno is good. Techno that fuses a techno beat on a classical framework may have been made for the specific purpose of keeping my brain in one piece while concentrating. It's really lovely.