Livin, FWIW Bondmanp and Programmergeek are correct about room set up being critical and responsible to your having a centered mono signal, but a stereo signal that is off center. While speaker location IS critical, in my room the listening position is even more critical. I had tried setting them up in a equallateral triangle which was off being centered on the center line of the room (that improved bass response some) but the center of my stereo image was left of center, closer to the solid wall (vs the other side which is near a 7' wide opening).
My solution was to place the speakers 1' from each side wall, severely toed in as described in my first post, and my chair was located on the center line of the room.
That may or may not be helpful to you in trying to solve your problems because of your room set up but it might give you some idea as to what is possible if you do something less traditional. BTW, firing that one speaker next to a wall and pointed straight ahead can create a difference in the signal (as opposed to the one with no side wall reflection issues). The severe toe in solves much of that problem. Unfortunately if the speakers aren't well away from the wall behind them, placing them next to a side wall is similar to placing them in or too near the corners.
Programmergeeks comments about the importance of symetry is right on. BTW, IMHO, tying to solve your problems with equipment will frustrating, expensive, and likely unsuccessful. Even a balance control won't do anything much for you if you already have a mono signal dead center. It IS the room and what is possible (or not possible) to achieve in it.
Hope that helps you a bit. BTW, some of us have worked a very long time to get a room with an excellent sound stage. Maybe we were just dense, but I think it is not that simple. :-)
