I think EMU may be the only ones who make sound modules that are design specifially for hip hop use. The PHATT line... Planet Phat, Mo Phat, Phatt Keys, MP-7, Phatt Phatt, Skinny Phant, Back Phatt, etc...
Everything else will works just as good with some creativity... If you are into dirty south sounds like MANNY then the Mo Phatt would be cool. If you are a PRIMO then you want a nice new sampler..... NEPTUNES = TRITON RACK.... DAVID BANNER = MPC2000xl....