i would get an electrician in so you do not have a power cord or extenstion wire in the wall. In most states if not all, it is illegal to run a power cord in the wall. all your other component wires can be placed in there.
if you do not want to get an eye level outlet for the cord we use a raceway that attaches to the wall you can hide all your wiring in. homeowners then just paint the raceway the color of the walls. It looks nice and if the next home owner does not have a wall hung tv they can just remove the raceway.