My living room is of a similar size and I played with it since I had a 7.1 receiver and some extra speakers. In the end I decided on a 5.1 setup. If I could have pulled the couch away from the back wall 7.1 would have been nice. However, the WAF prevented me from pulling the couch away from the wall. Her reasoning was that we could have a more "livable" living room for entertaining with the couch against the wall. If you are going to leave your couch against the back wall stick with 5.1.