It's not really rap OR rock, but clint eastwood by the gorillaz hits HARD right before Del starts rapping, i was tooling around with my system when i got my x's in, figuring out why nothing was hitting, and then BAAAAAM
my roomate and i just started laughing, it was nuts
and i'm not super into rap, but anything by ludakris hits **** good
"put your money where your mouth is" might be the name of the song? That one in particular gets low and loud.