I apologize for my negative attitude. I just felt like this was one of those, "I just want others to confirm my beliefs", threads. I have been all backwards for the passed few days and I apologize for jumping at you. There was no good reason for me too do that, I was in the wrong (very much so).
Back to business. I have only had to opportunity to listen to 2 channel Dolby TrueHD, and too me it sounds better. I hear dynamic compression with standard Dolby Digital, I do not with the lossless codecs. You are asking for a receiver that can do this, the RX-V663 will be the best in budget killing terms, of course there is always better stuff. What series Polks are you using? You might need a more powerful receiver such as the RX-V1800 or Onkyo TX-SR805 for example. The H/K AVR-445 is a rather hefty receiver and should have no trouble powering any Polk speakers I have seen, the Onkyo TX-SR805 and Yamaha RX-V1800 would be more in line with it in terms of power, with an edge to the Onkyo for power. The Onkyo runs very hot and many people don't like it for it's heat, size, and HDMI issues.