There are a lot of posts at the DIY forum of AA on running dedicated outlets, you might search over there for info.
You plan makes sense to me, I would have a dedicated outlet for digital, and a different run for analog, like you are suggesting. I did not see any mention of video power (this is a HT room right
). Would this be a seperate run/outlet too?
If this was me, I would probably do two things. Find 12 guage stranded THHN wire where all the strands are the same guage (Colonial wire and cable makes this, most of the others have different size strands). I have talked to Stan Warren at length on this wire (he uses it for IC's, PC's and speaker cables), and this is what he looks for, so it would seem to make sense for dedicated power lines too.
But, even if you just use any THHN wire, I would get the wire cryo treated. Somebody does it by the pound, so it would not be that much money. I would also use nice (Acme, hubbel, pass&seymour, etc) cryo treated outlets too.
BTW, I wish I could build myself a dedicated HT/music room. Must be nice