So, here's the thing. I have to disable local dimming because it introduces too much banding that I find way to distracting. For example, in Drake's Deception, there's a spinning ring on a black screen that is shown when stuff is loading. If I turn on local dimming, I see this faint white bar above and below the ring. Likewise for credits in the center of the screen, which causes the vertical area above and below the credits to be brighter than the area just to the left and right of the credits. This symptom has also been reported on Amazon, where the little LG magic cursor on a blank screen seems to cause area around the cursor to light up. This sort of thing drives me crazy. I believe this is a symptom of all LED edge lit televisions, as I noticed it on the Samsung ES8000 as well, but I'm no expert.
Here's a rather blurry image of this in action, with the TV hooked up to my PC, a black desktop, and local dimming enabled. (Please note that my camera makes this look blueish and much worse than it actually is, but it's still totally noticeable)
So, that's why I've disabled local dimming. Of course, when I turn it off, I get the clouding around the edges in dark scenes, which I believe is the lesser of two evils. Does this sound familiar or do you believe this is a defective set?
Alternatively, maybe there's another 47" TV out there that has the 3D quality of LG (i.e., no crosstalk) and doesn't have this problem, but I don't think there is one.