You could also consider the Yamaha YSP-1. It is an AH editors choice, and the review is
here. Its an excellent review, and it shows that you can get very good surround sound from this product after a little time spent setting up. It is a bit more expensive than the Polk, but its also self powered, so the power requirements of the receiver go down even more. Like Mark said, you could get a receiver down a few levels from the 2807 and save some money if you aren't considering the 2807 for certain features not included on the other models.