I've been jamming to a lot of ghetto hoodrat stuff while running like T.I. and The Notorious B.I.G. Also Kid Kudi's debut album is really upbeat and is filled with witty and inspirational lyrics, but he's not really a hoodrat, more prepster, lol. Of course more aggresive/angsty rock stuff like Nirvana and Alanis are always classic, as well as rock stuff with really epic soundscapes like Muse. And of course the capitol GAY stuff like Madonna and Kylie and Britney and Gaga are essential when doing cardio. I have a soft spot for Madonna's Hard Candy album when working out, lol. Sure, it's pretty dire, but it's got a lot of "just do it" songs like "Give It 2 Me" and "4 Minutes".