Reliable rap charts?

Chamillionaire, Kanye, Nas, Jay-Z, Common, Talib Kweli, Wu Tang, and basically most northern rappers. The south doesn't really have any good mainstream artist w/ the exception of Chamillionaire and maybe T.I.

North is the only cardinal direction I've never heard as having rap geographically associated with it.

East Coast. West Coast. Dirty south.

Never heard "North"

But then again, maybe Madison, Wisconsin has a really wicked rap scene I am not aware of.