After shopping around a little bit, I don't know if I would recommend the LED tech yet, it is mostly used by manufacturers to backlight the LCD and doesn't seem to have much of an actual effect on picture quality from what I've been reading. I don't think its worth trying to fit in that price range.
I would go for 120hz or 240hz LCD for LCD, it might not be noticeable for 85% of what you watch, but probably notice a difference on those fast panning sports games and the few bright color commercials out there.
Samsung has pretty much been leading the game, although I'm not a fan of their glossy screen, it does reflect a lot. The Sony Bravia line seem to do fine with an anti-glare coating.
Dusty has a point about the plasma. At naturally 600Hz and cheaper price tag, it does a good job. It won't achieve maybe the blackest blacks and the brightest colors and is a bit wider and heavier then the thinner LCDS, but the burn in images and such problems of the originals have been practically eliminated and they save you a third of the cost.