I think it really depends on if you are the kind of person who gets distracted by music, or the kind (like me) that finds it helps them concentrate. In school I HAD to have something playin, TV or music, to do my homework, or else my mind wandered too much. Probly some weird strain of ADD.
Also, anyone who finds they have to turn it up to loud should check out the thread in Riding Gear about earphones!