Thanks for all the advice everyone. It is greatly appreciated. In my current set up my rear speakers are mounted from the ceiling directly behind the seating area. So, what I am getting from you guys is that the 2 rear speakers should be mounted on the wall to the right and to the left of the seating area. And if I go with 6.1 (3 rear speakers) than that one will have to be mounted from the ceiling almost directly over the seating area?

If this is set up this way, than the wire for the 2 rear speakers will be running through an exterior wall that will be insulated. Do you guy's use any kind of conduit in the walls for your wiring?