All of your receptacles are 20A circuits? That's unusual - 15A is the standard in most homes, at least in my area. It would certainly be handy, though.

I agree that it is difficult if not impossible to conceive of a scenario where you could drive all seven channels of a home theater to 300W simultaneously, but an amp manufacturer still needs to provide at least the physical capability of generating the rated output. I suspect that very few 790's will ever get two dedicated circuits.

I believe that the fuse in my 750 is internal, and my equipment rack is not conducive to getting to the rear panel without an hour or two of wire wrestling. You might give Outlaw a call or try their support site to find out about the fuses - I bet they could give you all the info you want pretty readily.