The difference between your Yamaha and your friend's Rotel is not purely a matter of an extra 100 watts. I say that assuming that the Rotel in question is a separate power amp. Separate amps will generally yield better sound than receivers (their design is less constrained by space and shielding from other signals, allowing for a larger power supply and better cooling by means of bigger heat sinks), even at the same rated power. Amps are also typically rated more "honestly" - many 100W receivers will output 100W from one or two channels at a time but will drive all seven at once to perhaps 70W, whereas a 100Wx7 amp will typically be able to output 100W to all seven channels at once. (There are exceptions to this receiver-rating rule, such as Outlaw's Model 1070).

You could keep the Yamaha as processor, but the feedback from folks who have compared similar Yamaha receivers to Outlaw's processors suggests that the 990 would be an audible upgrade.

My day job is as a mechanical engineer doing HVAC design, so I have spent some time mulling over electrical nameplate data for things like amps, projectors, and such in order to figure out heat loads (which end up being very close to the electrical loads that my EE cohorts are concerned about). If you look at the nameplate data for everything in your list, you will find yourself wanting to run two or even three dedicated circuits. If you factor in real-world use, you will find yourself looking at numbers like that offered by nfaguys. Let's say you are really cranking your system with a new Model 7700 driving your DefTech's - maybe it's a screening of a Lord of the Rings movie or Revenge of the Sith. Even if one or two channels experience brief peaks of high power output (which would still probably not take everything that a channel of the 7700 had available), the other channels will be working at a lower level. And even if you've left both DVD players, the LD player, the CD player, and the HD cable box on, those units are drawing a pittance of juice each. The projector is the nearest thing to a steady load in your system, and that load can readily be defined by the wattage of the lamp (maybe 200W?). All told, you'll probably end up staying safely below the 15A capacity of that lone outlet you have feeding everything.