My system consists of primarily NHT.
2.5i, mains biamplified
1.5, surrounds
Audio Center-1, front and rear center
Sub Twoi, Front sub
Polk PSW650, Rear sub

I have nothing but praise for the sound quality of NHT speakers. Very detailed and open sounding but also very inefficent. (86db with 6 ohm imp)
Driving these speakers pushed me to upgrade to the 950/770 combo. So far I am loving the sound of the combo especially compared to the Yamaha receiver that previously held the position. I have listened to some of the other brands posted here (Paradigm, B&W, etc.)and thought they also sounded very nice. I tend to think the speakers color the sound more than any other piece of equipment, so when comparing brands or even different models within a brand you must listen to them. I have friend who thinks his Bose cubes are the geatest sounding things (ouch). Just proves the point.