I have managed bipolar (mostly depressive side) for 24 years, and I, too, have found music to be very hepful, but when I am feeling down, classical (I especially like Mozrt and Haydn) just isn't it, though it is something I immensely enjoy when my mood is more even. If I feel a slump coming on, my Mannheim Steamroller Meets the Mouse CD is the best therapy. Nearly all the selections are from Walt Disney movies and are so up,though Mickey Mouse Club is a bit somber. I just can't feel down, listening to such beautiful and happy arrangemnts. I especially have found "Hi Ho, Hi Ho", "Davy, Davy Crockett" and the absolute best lifter upper "Zippity Do Dah" to be helpful, and it's fun to sing along. I believe music is an excellent mood leveler, and I believe what's important is to find what music helps your mood, and then play it, sing it, dance even.
I might be bipolar, I am not really diagnosed yet.
However, if I am or not, music helps me. There are those days that I just can't concentrate, no matter how hard I try. I figget and take breaks and stare at the computer, and then I remember, if I get out my ipod and turn it on, that I can focus.
Sometimes it is hard to actually make the effort to listen to music, but every time that I do, it rewards me by helping me focus and get through the day. While not listening to my favorite music I can spend hours getting nothing done, and when I put the music on, I can focus for hours and get projects done that have been sitting on the todo list for weeks.
What I really need to do is listen to it more often and not get so wrapped up in the problem of not being able to focus and at least focus long enough to pull out the music when I sit down to do something.