For me it depends on what Im doing - weights or cardio. But for a spinning class, I love the following songs because you ride seated and then for the chorus you GET UP and put the pedal to the metal or whatever the saying is, haha and then you sit back song for the verse and up again for the chorus. It's great!
Womanizer - Britney Spears (cant stand her but this is a great pump up song for cardio, especially for any interval training)
Poker Face - Lady Gaga
etc. yeah its all top 40 but it gets me going for any sort of cardio cuz i workout HARD at the chorus...sweat til i cant sweat nomore and then the "break" is the verse.
Yeah Lady Gaga is getting old. I also really like to do cardio to things by the Black Eyed Peas, "I Gotta Feeling" in particular.
Additionally, the song "Gives you Hell" by the All American Rejects is a little slow but if you're not going all out (ie just warming up or cooling down), I like using it because once again, during the chorus you can up the speed/intensity of the cardio.
I also get all this music from ITunes that are remixed to workout stuff. Have a great version of Viva La Vida (I love Coldplay) and also of Chasing Cars.