Contrast ratio
In the world of video quality there aren't many specification more important than the contrast ratio -- if you enjoy movies or TV shows with dark scenes. Unfortunately, this also happens to be one of the most worthless specifications because every manufacture measures it differently. One of the latest tricks manufactures did was to introduce Dynamic Contrast. So instead of measuring the difference between the whitest white and the blackest black displayed on the screen at the same time, they display white and black on the screen one at a time and then measure the difference. Obviously this is next to useless, because this almost never occurs during normal programming -- of course there are exceptions to this, like alpine skiing or ice hockey. But it is the detail in the shadows and the ultimate appearance of black that is appealing in most programming. In the end the only way to compare apple to apples when looking for a new TV is by going to a trusted reviewer who always measure contrast the same way.