I have the TX SR-605 and it sounds amazingly natural and musical from bottom to top and the dynamics are fantastic. I can't really fault it except that it runs a bit hot. I doubt if any receiver under $1000 sounds noticeably better. Can't comment or compare the more recent SR-606 as I haven't heard it.
ANything beat onkyo for ht receiver $500?
Need hdmi 1.3, 3 0r 4 inputs, would like to go Denon but they are a bit pricey...