Money no object - Pioneer Kuro 50-inch 720p or equivalent - this would set anybody back at least $3,500
Typical model - Best Buy
They also carry the
Kuro / Cinema Pioneer true 1080p model a "steal" at $4,999
And that tells you all you need to know about true 1080p Plasmas - (typically carrying 1920 x 1080 resolution) they are at least 50% more than their 1080i / 720p equivalents.
I always preach that you get what you pay for with Plasmas - particularly the video chip that handles most of the smoothing functions - without which watching non-HD can be a royal pain in the rear. Pioneer has that licked.
OK - now if you want to be a softie with your deep pockets rich uncle, at the other end of the spectrum is
Vizio - their 50-inch 720p model is $1,499 - though at Circuit City that will be discounted to $1,200.
Not a bad set by any means. You may want to see just how it handles less than optimum signal input. Try to see if you can get the store to show a really dark background film - say on HBO HD. (Or the upconverted signal from a DVD like Lord of The Rings - bring along a copy of your movie and make them play it). If the contrast is not to your liking then you may want to look in the price tiers between Vizio and the top of the line Pioneer models.
Don't fall for the store wowing you with an HD Sports event - believe it or not even you will be watching a lot of stuff other than sports. So, you want a set that will be good at showing a broad variety of media - at different resolutions.
One other trick - have the input signal set to automatically switch resolution at set - so you can see how it handles switching from native 480i through 1080i (or 1080p if those pockets are really $5,000 deep). Then have it upconvert everything to see how that looks to your eyes.
EDIT - Per ORD - yes, more HDMI (or added component in a pinch) inputs area must. Most sets come with at least 2 these days.