My plasma keeps the "last picture" from when I turned it off until it gets exercised again (pretty much immediately), so no "burn in" troubles noticeable.
It does have a bunch of pixel-wide dead vertical lines, easily visible on primary color fields, not really noticeable on a movie or other mixed/moving content display. (that sucks, though).
So, one of these days I'll have to get a new TV (about 8 years old now).