If you're X2 just isn't cutting it, I would actually get an Fx-4100 or 4120 when they come out. While they may only have 4 "cores", remember that games can only use 1 or 2 cores anyway. Overclocked, the Fx-4100 will reach higher clock speeds than any of the other FX processors on air cooling, and is relatively cheap compared to everything else.
Otherwise, I would wait till Piledriver (although don't expect massive improvements), wait longer till Haswell, and just be satisfied with what you have for now.
Also, SHAME on you for getting a 42" LCD. You want 3D? Get a 42" or 46" 1080p plasma. All of them have astounding refresh rates (around 600hz), better blacks, better viewing angles, better colors... they're just better than LCDs, but only once you get to 42" or above. Trust me, I've seen
one: they blow any LCD I've seen out of the water. They're also pretty cheap now.
EDIT: Your 6850 is probably the weakest part of your system. Buy a 2nd 6850 for crossfire, overclock your Phenom II X2 to 3.8ghz or more on a good Aftermarket cooler, and you'll have a competent gaming machine. My 6850 is a good card, but they struggle at 1080p at high detail.
Also, I do admit, Plasmas don't do well in the sun.
On paper, the FX-6100 should be better for games, where single threaded performance matters (in theory, the 3 modules have a more advanced architecture). However, I think the 1100T and the Fx-6100 won't be too far off, I would get the FX just to try it new. A 2500k would be ideal, of course.