The flexible conduit mentioned above is a must. You always want the chance to pull wires. also, run an empty conduit with a string inside. you will be amazed how soon you will be using it.
On the walls, I would use two layers of sheetrock, but of different widths. I would probably put 3/8 against the studs and then use that newer fiberglass-based mold resistant sheetrock as the outer layer. This stuff also does not vibrate like regular sheetrock. I stumbled on this fact when I mounted some in-wall speakers in both kinds of sheetrock and the fiberglass stuff did not vibrate as much when I touched it while playing music. One other thing you might do is tack a layer of accoustic rubber between each layer of sheetrock. This stuff stops soundwaves really well.
On the walls, I would use two layers of sheetrock, but of different widths. I would probably put 3/8 against the studs and then use that newer fiberglass-based mold resistant sheetrock as the outer layer. This stuff also does not vibrate like regular sheetrock. I stumbled on this fact when I mounted some in-wall speakers in both kinds of sheetrock and the fiberglass stuff did not vibrate as much when I touched it while playing music. One other thing you might do is tack a layer of accoustic rubber between each layer of sheetrock. This stuff stops soundwaves really well.