I have, I guess, the 2007 model of the 63-inch Samsung 1080p set, the FP-T6374. I guess there's a new one out or about to be out in the fall.
Anyway, I'd agree with others in this thread. Samsung, Panasonic, and Pioneer are all quality displays.
When I was shopping around, I went to a few local shops and checked them all out. Really, the store is probably the worst place to go because the material they show is always garbage and getting to really play with the settings can be troubling.
But equally so, relying on forum chatter can be equally frustrating. If you follow AVS heavily, you'd be left with the impression that Pioneer is the only choice and everything else is substandard flotsam. Nothing could be farther from the truth, of course. Panasonic and Samsung would not be in business and have such high market share if they produced terrible displays.
I think that if you stay with any of the "majors" above, you'll be able to find plasma bliss. I'd be hesitant to put LG in as a major (even though I know they manufacture a dearth of displays) because they always seem to be more "cost conscious" in their products and Sharp always seems to be overpriced and obscure (difficult to find and thus difficult to service if needed).
Regardless, they will all produce amazing pictures with a bit of finesse!