Well I surely do not agree with Phasecorrect. With all due respect, I think it's ridiculous to assert that rock and roll does not deserve superior speakers or warrant spending $5k.
Are you trying to tell me that Pink Floyd's The Wall sounds just as good on speakers costing less than $5k as it does on speakers costing more than $5k? There are plenty of wonderful recordings of rock and roll that deserve good equipment. I personally listen to mostly classical and jazz but I love to crank a good rock album and a good system makes it all the more enjoyable.
Perhaps Britney Spears or highly compressed top 40 crap will not show off a high end system as well as a dynamic Mahler symphony, but I refuse to accept the idea that audiophile grade equipment is only worthwhile for a small percentage of recordings on the market. Virtually every piece of music I've ever A/B'd has sounded vastly superior on a good system. Of course, the better the recording the more noticeable the improvement... no argument there.