I bought the Panasonic 50" Plasma industrial/commerical model, not the consumer model, about a year ago. I love it! Have absolutely no complaints at this time. Was thinking of DLP, but really wanted the ability to hang on the wall. This replaced a rear projection TV, which I don't miss the BIG BOX. The difference being it is a monitor only, no tuners or speakers. Panasonic claims it has 60,000 hours til half-life. That's a long time. Most of the local dealers try to turn you off of Plasma, because the profit margin is greater on the other sets. The biggest thing to shorter life IS burn in. This is true with any CRT type screen. So I ensure I always have movement on the whole screen, no side bars, no games, nothing static. I use aspect change, picture position or what ever I have to do to fill the whole 16.9 screen. At night, about 2 AM, I have it do a screen saver program that slowly shoots a bright white bar from left to right with the remaining screen black. This runs for about 10 minutes. It "washes" the screen in a sense.
If you want confidence in a plasma for reliability, buy a name brand Japanese Plasma, stay away from the other Asian makers, as they rarely make the parts for their TV's, they buy from several sources and mix it all in. It might cost a bit more, but if your investing this much money anyway, go with the best, most reliable manufacturers.