Wanted: New Work Out Music

As much as I love the newest Foo Fighters CD, it's been on a long rotation on my iPod I use when I'm at the gym. It's time to infuse some new music (along with a new routine - mine is definintely getting dull and I'm reading more than I'm sweating). I don't like Pop music generally and am not at all up on what's going on there, but I do have a few Pop songs, embarassingly, that I like to have on my iPod for a lovely surprise during shuffle. I admit to having a Britney Spears song (I heard it first on Entourage, so that makes it ok, right?), a Justin Timberlake song (don't tell), a Kelly Clarkson song (I hate American Idol, but she can rock out now and then), an Avril Lavigne song (just shameful), and a few more I'll keep to myself. I like really upbeat feel good songs for the gym. Disco works sometimes (Jamiriquai is great for the elliptical - think Napolean Dynamite - Shelagh loves this song and danced with me in the kitchen the other night to it.) as does harder alternative like Foos. On the flip side, I also like mellow feel-good music for weights like the Garden State soundtrack...who knew I'd be doing squats and lunges to Paul Simon, but I do. I tried to just surf on iTunes, but other than listening to some cuts from singers I read about on blogs, it's a crapshoot. Any suggestions are much appreciated.