Good Workout Music

I've realized over time that I have to have good workout music to be able to have a descent workout at the gym or run. I think that having a playlist with good pump up songs is a great idea for anyone that wants a good session at the gym. I hate when I am half way through my workout at the gym and my ipod dies. I can't focus on lifting anymore because I don't have the same pump. Especially if i'm doing plyometrics or any sort of jumping exercises. I always have to have a good song to make me continue working out. Lately I have been listening to John Mayer and The Fray at the gym and I like it! It's not what you would think of as exercise music but it keeps me going, who knows maybe I just need to buy some more music. What do you guys listen to at the gym? Post your best songs in the comments section, I need some new tunes to jump to :)