If it is going in a room with a lot of light, go with an LCD...but ,make sure you at least get the 120Hz refresh rate on it, and splurge for the 1080p as well.
If it will be in a darker room, don't listen to these fucks...go with the Plasma. Make sure you get the 600Hz in the Plasma screen though.
I have been watching them close lately, and you can get a 50" Plasma 1080p, 600Hz in the neighborhood of $1,200 now.
Also, no matter which way you decide, go with the Samsung.