For the power, I'd suggest cryo'd 10awg romex. You can get this from either Audio Sensibility or VH Audio. It's pretty much $3/foot. I would setup 20 amp circuits instead. If you got the money, go for Furutech rhodium outlets (or equivalent). Hubbell hospital grade outlets are good for high-current, but they do have their own sonic signature, which can be forward and solid-state/sterile.
For in-wall speaker, I don't know. By code, it has to be CL rated, so you're pretty limited. I dunno, Audioquest FLX? You'll be able to get a better speaker cable if you just run it inside the room.

