BTW, based on this thread (and being cheap), I went ahead and picked up a Samsung 50" plasma. I got it for the conference championships (honest my Packer-fan-wife, I got the new tv so you could enjoy the game better....)
Only $650, so way cheaper than LCD tv's, and a far, far nicer picture than the sony rear projection LCD it replaced. Perhaps not as nice a picture as a high-end LED-LCD, but great for us since we're not huge videophiles. I compared it against a Zenith (made by LG) 50" plasma that was only $550. I liked the Samsung picture much better. I agree it is hard to compare in a store not knowing how it was set up, but though I couldn't adjust the Samsung picture, they had left the remote for the Zentih lying there. I spent a lot of time totally changing around all the settings and playing with everything, and nothing I did made the Zenith look as good as the Samsung positioned right next to it.
I spent some time with my Digital Video Essentials set up disk to really try to tweak the settings (damn there are a lot!), and really have it dialed in pretty good at this point.
I don't notice anything objectionable in the way of noise from it. It's in our family room in a finished basement which though it has plenty of windows, doesn't get strong lighting, so the brightness on it has been fine.
Overall, a great tv for the money. For our watching habits, it is hard to justify spending $2000-3000 for a tv (again, did that once already), and the plasma has fit the bill nicely.