What's good music to listen to whilst you're doing work and revising?

I've noticed that a lot of the music I listen to when I'm doing work doesn't distract me in a way that makes me sing or write down the wrong words or whatever, but instead puts me on edge and makes me feel uncomfortable and slightly uneasy. I think it's because of the tempo or the different types of music i listen to thrown in together because i usually have my ipod on shuffle.

It's not all the time this happens and I have to listen to something when doing work other wise i get distracted easily by the television or my very loud and large family who are simply doing what they usually do.

I looked at one of these forums written by someone else and a lot of people said classical music helps - but then i came across someone who said that the Harry Potter Sound track helps them. I liked the idea of soundtracks so I was wondering if there's any other soundtracks that might help in similar ways?