Monoprice
I had my theatre room fully wired by my low voltage contractor. If you can, buy everything in advance and supply the wires, connectors, wall plates, etc. to him. One word for you, "monoprice.com" (well, I guess two words). Bought all my wall plates, connectors, etc. from them. Good prices and solidly built. Even bought the 7.2 gang plate which is about $20, but it does make everything clean and simple for installation. Don't forget to run at least two HDMI's to your projector (just in case one craps out). Also run Cat5 or 6 to the projector as well as AVI. Even though you think you may not need it, it's cheap to run it now since the ceilings all opened up. Once it's closed, it's pretty much impossible to run stuff. I also left a few pull strings in the ceiling for future. If there's too many twists and turns, I would just put in a piece of 1" elec conduit with a pull string (keep the bends to a minimum as He-man won't even be able to pull a cable through if there's too many bends). When everything is pulled, make sure you full insulate the walls and ceiling. This will it somewhat contain the noises in your theatre room. If you can, ask your contractor about accoustic ceiling panels prior to drywalling. Good Luck!