the image tends to burn into the lcd's more when its the same image there for a long period of time. as the plasma does not as much and they usually come with something that prevents it from happening.
Actually, not only are LCDs actually less likely to suffer from image burn-in, it is actually impossible for them to burn-in because of how the technology works. They work by blocking the light from a light source external from the displays themselves which means images can't burn in. Plasma displays generate the light on the display itself and can burn-in for that reason.
Back on topic: I would get an LCD because I think the technology is better and more mature. I think plasmas are beginning to be phased out.
