I had a new Plasma TV recently develop a screen burn/image retention by playing a game on it for around 90 minutes, also any still graphic (if your unfortunate enough) can burn in to the screen. Once its there its there for good on most occasions.
Below is a link to a review on my replacement LCD tv, in this review I go on in more detail about my experience with Plasma.
Some people have Plasma's and have no problems, I don't think I could own another Plasma as I would be paranoid about screen burn. A lot of people say screen burn/image retention is a thing of the past with Plasma's, but in my experience it is still and issue.
The brand was Panasonic, I would have to say that it was a burn in as I had it for a little while after and it never faded/went away.
I done a bit of research on Plasma's before buying and the general opinion was that Panasonic (some people said about Pioneer as well) been the most resilient to burn in/image retention.
I did ask prior to purchase if it would be suitable for games console use and I was told that,
"If you had asked me that question a few years ago, I would have had to have said no, but image burn/retention is not an issue with modern Plasma sets."
All I did was play for no more than 90 minutes (which isn't a long time) a racing game from my PS3, after I had switched it off, on dark TV programs I could see the speedometer from the racing game. First I thought it would go away, but it never budged or faded, so in the end I went back to the shop and got it exchanged.
The LCD TV I got (also a Panasonic) is IMO a lot clearer/sharper/vivid picture than the Plasma. A lot of people say that LCD TV's cannot show deep blacks very well. The LCD TV I got has a varying backlight brightness which dims when there are black scenes, this works well and IMO shows blacks as good as the Plasma did.
Some people are lucky with Plasma and have no problems, but I guess I wasn't one of them.
The below link is for a review I wrote on the LCD TV that I got in place of the Plasma.
This is just to acknowledge with many thanks all the input on this subject so far.Your input and interest and indeed advice is much appreciated.
I have not yet really made up my mind but am coming round to thinking that a 40 or 42 Inch LCD might be what I will select in the end. As Panasonic don't seem to do a "favoured" one in those sizes , I will probably go for a Sony.