plasma appears to be the best picture, hands down. keep in mind that they reportedly have a lifespan of about four years. this is according to a few friends of mine which work in the electronics biz.
I'm in the market for one too...just can't bring myself to spend the money. I'm a real tight ass when it comes to me.
Plasma is so much brighter, especially at angles. Don't get me wrong, LCD has made improvements, but plasma is still king. No need to darken a room, and even though they say it's not real, I still seem to see motion blur with LCD.
The thing I like about plasma is that there is no such thing as a 'viewing angle'. The picture remains crisp and bright regardless of how far to the side of the set you move.
Panasonic makes a plasma EDTV (not HDTV). The picture is equally amazing IMO as HDTV and its some cheaper. Don't know much past this.
IMO, if you have the disposable coin, get the plasma. Apparently they're fusy machines though. You have to shut them down a certain way.
I'm gettin an LCD, next Christmas.