Also, some speakers sound their best at moderate to high sound levels and do not do well at low listening levels and visa versa (amps also effect this nature). Unless you have a great deal of money to invest it is probably best to try and balance your system to your musical taste. I listen to most types of music, but do not listen at super high SPL's and am very happy with Reynaud Twin speakers. They do not have low bass and do not play extremely loud, but on the other hand they have an almost electostatic quality at very low listening levels (but with dynamics at higher levels). This was my goal. Most people think of a "rock" system as being a headbanger system. It does not always have to be that way as my system sounds very good with rock, I just can't blast it to a concert level. My old speakers were great on classical and small group pieces but were not enjoyable with R & R. I opted for new speakers that were more middle of the road.
Rock and Roll Snobbery
Can anyone explain why otherwise high end, musical systems might "not be good for rock and roll?" Or why a system that sounds fine for pop and rock might not do justice to classical and jazz? It seems to me that a great system should sound good with all types of music and that a good for classical system might be deficient in bass which is not exactly state of the art.