IMHO the secret to rock music is to have a system that controls the bass, has detail and an attacking edge to it.
My present setup initially sounds bass light. But that is because it is very tight and does not bloom and muddy the bass to lower midrange of the music. I get great detail with things like a kick drum which sounds really clear as the notes start and stop very quickly. That then gives the music a dynamic edge and that suits rock music. A lot of rock music has a wall of sound recording style and detail, by which I mean being able to hear everything that is going on, means the sound is given a lift away from it all sounds at one level.
Baldybounce, for a one box rock system I would look to an ipod and Bose Sounddock. The bass on the Bose is very well controlled. For example the opening of Massive Atttack's track 'Angel' distorts on every set up I have heard, except the Sounddock. It also has detail as there is a 'meow' sound at 29 seconds which is clearly sounded.
If you go down the spearates route, whatever the system, you want to pay attention to the speakers. Making sure they are secured on decent stands that themselves are on a secure base and watch how they are positioned. Moving a speaker closer or away from a wall, corner can make a big difference. The aim is to make the speaker able to handle the dynamics of good rock music.