Thanks to all who responded so far. I would like to make it clear that my installer is just a professional that my company has had dealings with. I'm getting a new LCD and since I'm going HD, I want to get a receiver with HDMI. I currently have a Yamaha RX-V659. there has been no analyzing of my room to determine what would work best.
I don't need the installer for the receiver, but since I'm getting a new TV and will be mounting it on the wall, I'm having him take care of the entire installation.
The Sherwood R-772 will cost me ~$250 more than the Onkyo. I don't know what I get for the extra $250.
I'm pretty sure that the Sherwood doesn't up-convert lesser signals to HDMI, only up to component.
I'd like to hook up just HDMI, since my new Sat. receiver and DVD player will have HDMI outputs.
I feel I won't be able to hear the difference between any of the receivers, my ears are just not that "in tune"
If the Onkyo's heat issue really isn't that big of a deal, I feel that would be fine for my novice ears.