I have a 2007 42" Panasonic Plasma(and my blacks are superb, unlike the person that previously said their 2005 model had problems). I have had a PS3 and used it for 2 years. In addition, I watch a lot of channels that have big steady logos on the screen all the time. I have had zero burn in. Only temporary image retention from polarization, if say having a fixed image/logo on the screen for 5 hours a day for a week straight, which was always cleared away with a day of playing content with no fixed images/logos.
LCD just does not cut it for me for television use; they are not comparable to a good plasma yet. Even for games, I highly prefer the smooth contrast and huge color gamut that plasma provides. And the lack of any image blur/ghosting is another considerale benefit.
Perhaps if you play the SAME game every day, with virtually no other video sources or games to switch up the fixed pattern(s), then maybe you would have real burn in problems on say a modern Panasonic plasma. Otherwise, I just don't see any real reason for concern.
-Chris