While I've read many of the threads about the Reon chip vs. Farouga and so on, I don't know of any side by side reviews of the Denon, Onkyo or some of the other new 1080p AV Receivers. More importantly, I have been looking all over for the Onkyo TXNR905 and nobody seems to have any in stock, and I have also looked for professional reviews but couldn't find any either.
Circuit City is just now getting the Onkyo 875, they have it listed at $1700. They also have the 805 on sale for $899.
There is an awful lot of speculative hype in the Onkyo units, which may be warranted given their impressive spec sheet, but I will never buy another piece of audio equipment, especially a $2000 receiver, without first demoing it personally with my own material.
Last weekend I did a side by side comparison of the Pioneer Elite VSX92 and the Denon AVR 3808. I didn't actually compare the video signal processing in them since both are Farouga, but the sound was vastly different. A lot of us tend to speculate based on just what we read in the manufacturer specs or from blogs, etc. But there is still a lot to be said about using your own eyes and ears to judge for yourself. In the end, the sound quality of the Denon literally blew away the Pioneer, which was not at all what I was expecting.
I suggest you get out there and visit some audio shops that will demo the equipment for you and let you compare them side by side. You may be quite surprised by what your ear prefers.