Simple Solution, I've done it 3 times already!
I have been to like 10 different BBs, CCs, PC Richards, Sears, etc, and I was able to do this simple side by side(well not exactly side by side)test on 3 occasions so far. Here it is: Took a certain Movie by Disney Pixar with talking CARS in it, and another certain movie with Bruce Willis in it (Live Free or Die Hard), and had them played on both a Plasma and a LCD.(both 1080P) One time with both sets playing the same movie, at the same time with the DVD signal split to both sets, and one time with seperate dvd player hooked up to each set. Not the sales person, not me, and not anyone else who happenned to catch this demo could deny that the PLASMAs had a better PQ no matter what brand set was used, and the screen sizes were all comparable too. BTW: Lighting was "normal" in every demo. The action was more on the money with plasma, the colors more vibrant, and every detail more precise. Of course this is only MHO, and everyone else's HO that witnessed these demos. I know I am going to hear about the lack of a demo on broadcasts, but in all honesty, the few Basketball games, or Soccer Games that I noticed on a few occasions, looked as sharp as ever on the Plasmas too. But the movie test told me everything that I needed to know in order to pick the winner in this LCD vs. Plasma dilema.
Take care all, Joe B.