I would advise ANYONE looking for a plasma TV (or any other TV for that matter) to go to the AVS Forum (I listed above) and do a bit of research.

When it comes to burn in and the actual life of plasma TVs, no one really knows for sure. Many things have been said about "refilling" plasma TVs, which is totally false. People wonder about how long plasma TVs last, and many have stated they have seen some from 1995, being run 24hrs a day in banks and what not, just now being replaced because they stopped working. I saw a post, taking into account the average life in hours stated from almost every manufacturer of plasma TVs, which came out to about 22.5 thousand hours, running at very high contrast. Given that, on average, most families watch about 5-6 hours of TV every night, that comes out to around 10 years (6 hours a day). That's not to say EVERY SINGLE plasma TV will last that long, but not every single CRT will either. All I know is, for me, I usually don't keep old technology for 10 years or more... it just depends on what it is. Computer parts for me last maybe a year, but my VCR has lasted 6 years!

There are also a few things you can do to extend the TVs life, like turning it off when not using it, adjusting the brightness and contrast, keeping it in an area where it can get good airflow (don't stuff it in a box and use it for some reason) and there are others.

As for playing games and what not on your TV, or watching a lot of TV and "messing" the TV up somehow, I think there are a lot of misconceptions. Most plasmas, if not all, show at least 16.7 million colors these days... with some newer ones showing a little over 1 billion (per Fujitsu specs). With plasma, you can get a burn in... like on an LCD or CRT, if you leave a still picture up for a period of time, the image "burns" into the screen. The same thing happens on a plasma, only you can sometimes use a grey image, leaving it on the screen, to help "reset" the burn. Also, if you watch movies where the ratio leaves black bars on the top or bottom of the screen for a period of time, those bars can burn in a bit as well. I believe this is usually help with the grey image method. Plus, as with the newer Panasonic plasmas, they have a 4000:1 contrast ratio, which may or may not be good for games on a 42" or above screen... I don't know having never tried it, but I don't play games on my TV anyway as I have an 18" LCD monitor for my computer.