I have seen so many problems with samsung displays on TVs and unfortunately just experienced the same issue. Just a little over 2 years after purchase I am experiencing the same issue as many users of Samsung TVs. My TV started to display a constant shadow on the screen. Of course Samsung does not want to repair it as the warranty expired 2 months ago (pretty convenient timing).
This was the first time I bought a Samsung TV and the last time for sure. If you are looking to buy quality just look somewhere else, you can buy far better for cheaper if you look for chinese brands TVs.
I will write some reviews in TV forums and hopefully save some money to other people looking for a new TV.