After much reconfiguration, my HT set up looks a lot like Pogre's. In our living room, my challenge is more like Adam's.
There I use a subsat config and forgo the center. Have used 6 centers and found most of the are difficult to integrate, I eliminated it. I concur that towers should be away from walls, but can say that my satellites are in a shelf unit and are ok for movies and casual music listening.
In any case, would work to get speakers towards front and away from cabinet edges. Also, more importantly, tweeters close to ear level.
Ww