I too have been looking to upgrade from my aging Sony STR-DA50ES in about the same price range and know how tough it is to make your mind up! For slightly more at $599 the Pioneer SC-1222-K makes me drool! You can find it sometimes on the egg for low $500ish range open box. The Yamaha RX-V473, 573, and 673 are all in your price range. By what Ive read, the 473 and 573 are the same unit except the 473 is 5.1 and 573 is 7.1. As far as going for a 7.1/7.2 vs a 5.1, ask yourself are you really going to use the 7.1? If not, its a waste if you can get the same features and quality in a solid 5.1 for less. I hope this helps some as these have made my personal short list!
Samsung 51" Plasma E530, Pioneer SC-1222-K, Sony BDP-S5200, Roku 3, Custom HTPC/XBMC, KEF Q600c -center, KEF Q900- mains, Definitive Technology SM450- side surrounds, Definitive Technology SM350- rear surrounds, Custom sub 'end table' with 12" Oz Audio Matrix Elite, Crown XLS 1500 sub amp, Harmony 650 and IRule remotes