I know you didn't get many responses. That is sort of because at that price point nothing can really touch the performance of these setups.
The 770 is just under $500 most places.
CC has the Onkyo 760 system on close out for $380 or so.
http://www.circuitcity.com/ssm/Onkyo...oductDetail.do
The subwoofer in the 770 system is enough to warrant the extra $100, but the 760 system is also a real over achiever performance wise.
Anything less than something like this is going to sort of cheat your Multi-Channel surround experience. In my opinion anyways.