I just found this website (and the mountain of available information) after searching over the internet about a recurrent problem I experienced with HDTVs: backlight leakage. I can not confirm that all LCD HDTVs have clouding/flashlighting at a certain degree, but here is my little story.
I believe I am a very patient individual, and I really wanted to get a cloud free / flashlight free HDTV because it annoys me to no end, so I decided to return problematic HDTVs to the store until I found one perfect. However, it still has not happen and in the last 3 weeks, I have been through 10 HDTVs (ten, not a typo). I bought/exchanged 3 SONY 40V5100 that had very bad flashlighting in the two top corners. After the third return I decided to give a try with the Samsung LN40B610. I have been through 4 Samsungs, all with flashlights in the bottom corners, and two of them had very bad clouding and viewing angle, as if the LCD panel was not the same as the one used in the others.
Finally, I tried 3 SONY 40W5100, having been told that the screen uniformity was better on this model (it is indeed the case). The first one had flashlight in the two top corners, but no clouding, and the top of bezel was scratched (built August 2009). I returned it for another 40W5100. The replacement had the same flashlights in the top corners, but the worse was the clouding all over the screen and the blueish/purple tint of the screen as soon as I was a little off axis. I have a very hard time to believe the panel was the same as that of the first one I got. The built date was July 2009. Finally, I brought pictures where I bought it and I got another replacement, as I was told by the seller that the amount of clouding and flashlighting was not acceptable. Believe it or not, the new 40W5100 has a flashlight in the top right corner, and the top of the bezel was scratched in two places out of the box. I think I'm running out of steam now, and I think I am going to live with it (try at the least).
And by the way my backlight level is set at 2-3, with brightness set to 50.
The baseline is this, if any of you got hand on a SONY or SAMSUNG set that has NO flashlighting at all, I think you may definitely consider yourself a lucky person.