I find that music is of utmost importance during a workout. "Back in the day" I thought that - along with wearing worn-out workout gear - I HAD to listen to HEAVY stuff for it to count as a workout. I would put on the Pantera (Vulgar Display of Power), Sepeltura, Prong, Megadeth... I realized one day that all I could focus on was the music! I wanted to drop everything and start thrashing around and screaming the lyrics. I guess I'm ADD.
One day I was hiking and listening to a meditation tape (yes a cassette - remember those?) and found myself pushing hard with a more focused attitude. So, I started to listen to this style whenever I workout! Amazing results! Now I look for meditation, ambient, drone stuff for my workout.
Quiet Heart/Spirit Wind (Native American and Asian flute)
Ravi Shankar - Chants of India