Tacmc5 - A lot of the responses here are from people who are clearly close-minded about music, and really don't know what they're talking about.
To answer your question - Yes, definitely, many high-end speakers and other components are GREAT for rap and rock. Wilson definitely comes to mind. Recently, I spent some time with the Alexandrias at my favorite high-end dealer. I played Snoop Dogg, Guns n Roses, Yo La Tengo, Radiohead, and lots of other stuff. My dealer was in the room when I was playing the Snoop. He loved it, as I don't think he had heard this type of music on these speakers before. It was incredible!
For all of you playa-haters who claim "no rap is decently recorded, blah blah" or "anyone who likes rap should be shopping at best buy" sorry, but you are just plain wrong. Listen to Tupac's "all eyez on me," anything produced by Dre, Nas Illmatic, anything by Tribe called Quest, De la Sol, Biggie "Ready to Die," the list goes on. All sound great, and these are original, masterful pieces of art.
The better the system, the more fun the listening.
Von Schweikiert would probably also be good