What do you primarily watch/listen to, music, movies? Most A/V processors/receivers do one or the other fairly well, unless you spend over a grand, then most do both well. Look for 6.1, which means you will have to rethink your speakers because you will have to add a center rear to the room. Believe it or not that extra speaker really makes a big difference. I prefer Yamaha, I have owned various Yamaha processors for years and have had really good luck with them. My current A/V receiver is a RX-V1, which has all of the above and front effects as well. They were originally about $3000, but you can pick one up on e-bay for around $1000 or less now. It also gives you the option to add external amps for all channels should you want to use tube amps. It all boils down to a matter of taste and how much you are willing to spend.
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My System:
Mitsubishi 65908
Yamaha RX-V1
Panasonic DMRE30 DVD RAM
Pioneer CLD3080
Chorus II (Main)
Academy (Center)
Forte' II (Rear)
RCA Lineaum(Center Rear/front effects)
Yamaha M-80
RCA right/left sub