I own an 805 and I agree w/ Chopin Guy that the 806 is a downgrade from the 805. eBay usually has some open box new 805s for sale. Might even find an 875 there which is worth the extra money over an 805.
I have owned several Denon avrs. I like thier sound better than the Onks, but not by much. Denons also have a better build quality than the Onks, but, again, not by much. This is why they cost a bit more than Onks. However, Denons are a pain in the *** to set up and operate for home theater. The User Manuals might a well have been written in Japanese.
Def check out comparable Yamahas, Pioneers, Outlaw and Emotiva. Harmon Kardons have a good rep, but they are underpowered if you are gonna run large front left & right speakers.
Mike