For rock I recommend older Klipsch speakers. They are horns, but the old ones are not bright or harsh. They are incredibly efficient (LaScala's at 104db/watt). They are also incredibly dynamic, which is what you need for compressed rock recordings. What they don't do is image very well. They play very loud and tonally very accurate, but do roll off at the top and bottom ends. Their other downside is their size, so if that's an issue you might consider Klipsch Cornwalls.
What to do? What to do?
I need to acquire speakers for my system (Acurus ACD-11, Aragon D2a2,Aragon 18k, kimber 4pr and pbj). I currently own a pair of BW 620 (free for helping my neighbor move). They've never wowed me with my rock music (which is about 50% of my collection) but I enjoyed listening to chamber and jazz on them. I'm a grad student and this will be my first real speaker purchase, so budget is an issue. What direction should I take in my search for some accurate speakers.