I usally listen to hiphop, reagge and indie/pop.
When I grind I listen to eletronic music like trance, EBM, industrial, darkwave and indie/pop. So it's alot of Groove coverage, Cascada, Bright eyes, Front 242, Welle: Erdball, VNV nation, Depeche mode, And One... :3
The pumping electronic music kinda takes away everything in my head so I can just grind like hell. :]