Backlight leakage and banding in the LCD panel are the two most discussed problems with LCD tvs today. However, I think there is another problem that probably deserves even more discussion and hate, and that is "the dirty screen effect".
Pretty much every single TV maker today has decided to coat their screens with a chemical mix that is supposed to decrease reflections. This coating ends up doing very little to improve reflections, while it has the horribly unfortunate side effect of putting a dirty looking layer of filth between your eyes and the content the TV is displaying. This is so distracting I'm amazed more people don't have a problem with it.
In 2011 I was on a quest to find a TV that didn't suffer from this problem, and had a low enough input lag that I could happily play games on it. I found that TV in the Panasonic D30 LED/LCD. This TV had absolutely no coating applied to it's screen, and the images are fantastically clear because of it. The only downside with this TV is that they only made it in 42 inch sizes.
So this year I'm hoping to replace it with a larger TV, and unfortunately I've now learned even Panasonic has decided to apply these "anti reflective" coatings to their TVs. Of course the results are utter crap. Reflections are still everywhere to be seen, AND now you've got this ugly filth everywhere you look.
Sony and Samsung are actually worse when it comes to this coating, as their coatings seem to be using and even darker compound that makes things look even "dirtier". I recently bought a Sony 802a TV and it was a mess. Returned it for another one, and the problem was exactly the same.
So when is the TV world going to smarten up and realize these coatings are doing absolutely no good for anyone, and they're actually greatly crapping up the image quality of these TVs.