Hey again, TheFactor. If using THX, I also wouldn't worry about burn in. My brother's entry panny had nothing at all about preventing burn in inside the manual, when I perused it, and that was last year's model.
I noticed your query in the amps subforum. If you find from your research that you really don't need to add an amp, and you got money burning a hole in your wallet, I would do acoustic treatments.
I note that the new pics look like a completely different orientation than the pics in your sig, and maybe it's a different room entirely. You could definitely treat the front wall, and I can't see the side or rear walls, but perhaps they would make for candidates. Of course, there's the ceiling too.
Question: Is it possible, or is there enough space on top of the AV stand, where the TV can be pushed back some, so that the center speaker can sit in front of the TV? I don't know how much taller the speaker might be than the bezel of the plasma, if at all, but if you can make it work out, even if doing something to raise the TV height slightly, it will sound better. I am assuming the IR sensor on the TV is on the extreme side of the unit, and not smack dab in the middle like with some Samsungs. Even if it was, you can get around it with a RF/IR emitter.