I've always enjoyed my Polks, but never quite been totally happy with the mids and highs...kind of muddy--turbulence type sound. Well, I added a NAD 218 (225x2) Friday--passed it through a Denon and immediately noticed huge improvements (much more than imagined). WOW i can't believe the difference. The Polks highs and the mids are clearer and more defined...they seem more open sounding, like they have been unleashed. The Denon has a smooth..neutral type of sound and the NAD mixed in well. These improvements were through CD play, I then turned on the DTS LOTR dvd and the improvements here were also noticeable, not as much as 2-channel, but they were there. The musical score was alive and made for an enjoyable night.
I purchased the amp with a future higher-end speaker purchase in mind..but, now the Polks are staying and i'll go the separates route.
If you guys want to push the Polks...try a separate amp and take'm to another level.
Polk RT2000p (front)
Polk CS400 (center)
Polk RT15i (rears)