This happens with all video sources.
I have a Samsung LN52A650. When looking at the screen I see a vertical line down the screen. everything to the right of this line seems slightly dimmer or darker. I bought the tv just over a year ago. 5/27/09. Does this sound like the backlight? Do you still get 3 months extra warranty when you register your product online? I already had the screen replaced last year with a black horizontal line acrossed the tv.