What really gets me pumped up is almost anything from the Step Up soundtrack. 'Show Me the Money' and 'I'mma Shine' are two of my favorites.

Here are some more of my favorite songs to work out to:
Stronger - Kanye West
Don't Stop the Music - Rihanna
Pon de Replay - Rihanna
Get Busy - Sean Paul
4Ever - The Veronicas
Lala - Ashlee Simpson
Ring the Alarm - Beyonce
1, 2 Step - Ciara ft. Missy Elliot
What I Want - Daughtry
No Sleep Tonight - The Faders
...and almost anything by Fall Out Boy
I'd also have to vouch for what Anna said about the iTunes podcasts. I have a couple on my iPod and they're great to listen to when you're running!