The Yamaha will probably be fine, depending on what you consider "reference levels". The Axioms are extremely efficient speakers, and don't need many watts to play loud, even in large rooms.
If you're wanting headroom in a powerful amp for home theater use, have you thought about the Outlaw 770 with a good processor? It could save you big bucks compared to the flagship receivers.
I don't know if any receiver (or even top-of-the-line processor) offers three wideband capable component video inputs. If the Denon or Sunfire offer three, that's pretty impressive.
Firewire is being proposed as a means of copy-protection-friendly digital transmission of HDTV and DVD-A material. So far, only analog connections have been allowed. I believe there is a Pioneer DVD-A that will put out the high-resolution surround mixes to a receiver through the FireWire.
Best of luck
