I usually listen to jazz of various kinds, but yesterday put in Bach, Vivaldi, and also logged on to the Superlearning site you mentioned and I do think it's helpful (I'm taking time out to study/review for a 6 hour examination this Thursday).
I use music a lot, always have what I want to hear on in my office at work. Agree that for studying, learning, anything which has its own words ("lyrics"
) it makes sense to have instrumental music. Also a steady beat not too fast, not too slow, 60 seems just right.