I’m curious what choices you have made and what you think of your sound. I have a 12X20 living room too. I have the Tv and sectional/chairs on the long walls so there is a short distance between the TV and sitting area. I started with the QIII’s with a Klipsch 10” sub. I always planned on upgrading a little at a time and I recently found a great deal on a set of F-3’s. I simply added them thinking it would be just fine, but I quickly realized just how much more the F-3’s were out-performing and over-powering the QIII’s center channel. I completely agree that you need a better match up front because simply adding decibels to the center channel didn’t help. The sound either comes off way to harsh out of the center or I loose the advantage of the F-3’s by keeping the overall volume down.
However, I am still using the QIII’s for surround. I have no doubt that I will like the S series far more, but the QIII;s really aren’t that bad. I did increase their levels a little bit to keep up with the front, but the speakers are not too far from either side of the sectional so they still sound nice. It all comes down to getting the most for your money. If I had the ability I wouldn’t be in the Synergy line ;-). I will get some S-2 or 3’s soon, but I am content with them for now.
If you did keep the QIII’s, let me know what you think of them with your F-3’s and what you did for a center channel.