if you are considering a plasma and reading this thread, IR probably won't be a problem if you follow these rules early in the life of the TV:
1) make sure pixel orbiter stays enabled at all times, no matter what, Unless you are watching a blu ray with NO black bars. Pixel orbiter only stays enabled when there is some extra "screen space" outside of the viewing area, ala zoom mode, or in the case of the ST/GT/VT sets, you can also set to "size 2" in aspect menu. either one will work. Otherwise the pixel orbiter WONT be enabled. I must emphasize this for video games and cable especially!
2) when watching cable or playing video games, DO NOT use THX mode (neither regular or bright room) for the first 250 hours minimum! Use STANDARD mode instead. Trust me.
3) if logos, scoreboards, tickers whatever are present on the screen during cable, try to zoom them out as best you can. I think the best course of action is actually to alternate zoom and regular mode every 30 minutes or so if you can't completely zoom out the offending image. This is ESPECIALLY important for video games like mass effect 3 where there are some white images that can't be zoomed completely out of view.
4) after about 500 viewing hours, you can ease up a little bit. maybe watch THX mode during regular cable if you alternate channels or the zoom mode like in #3. I would still keep it in standard mode for video games though.
5) after about 1000 viewing hours, you can probably ease up a lot more. use THX while gaming, cable etc. I would keep pixel orbiter enabled anyway, but i would say 1000 hours is the cut off for truely "safe" viewing. If you don't want to follow this procedure, you probably don't care enough about the quality of the picture therefore just get LCD. Neither technology is for everyone.