I am quite happy with my new Samsung 1080p plasma.
I was very surprised to find out how limited the stretch modes are.
For DTV (ATSC) - there is a wide mode which is great to stretch 4:3 to fill the screen. Many manufacturers (like my LG plasma) do not do it.
For SD content, the Sammy only does 16:9 linear stretch which I don't like but I have to use. Ridiculously, there are two vertical stretch modes, one more or less just blow up so a 1.78:1 letterbox and will almost fit the whole screen which is good and the aspect ratio is almost correct again. The other vertical stretch mode stretches 2.35:1 to fill the whole screen that I find ridiculous to use. It is more of a anti burnt-in feature than for viewing.
My LG plasma has good SD stretch modes. I love the HORIZON non-linear mode for default use. Mode1 (1.78:1 vertical stretch) is great for letterbox. Mode2 is an in-between linear stretch/crop.
I played with a couple of 2nd tier brand as well and the stretch mode are generally not as good.