[JET]

You really need to balance the speakers with the amp. The head units are a bit closer now, but if you get something like a Denon, they are really bright and you want a speaker that isn't as bright or your ears will kill you. H/K is good, but their features are usually a little behind. Best bang for the buck on a very nice system is almost always the Sony ES line. Top notch features and they use nice guts inside. They also tend to be very neutral for sound.

Speakers are subject to a lot of things, mainly your taste and your head unit. Do a lot of research at avsforums.com and you can make a good choice. Subs, you can't make up for size. I have a faily cheap Cerwin Vega 15" with 250w RMS amp built in. The thing rocks and is probably 15 years old now. A higher quality 15" (possibly 12") would be the way I would go. I had a nice 10" also and the explosions in movies just don't feel the same, even though they are as loud, they are as deep or carry as much force.

Def Tech has been the speakers that I like the most, if I had the cash. They have matched speaker systems for HT. The Mythos ST/STS series is awesome, strap a Supercuber reference sub (1800W 14") on to that and hold on!