For LCD's get the highest screen refresh rate you can afford. LED is an LCD display with LED's either behind or to the side of the display (behind is far better). Good brands are Sony, Samsung, LG and Panasonic. Vizio has a lot of features for the price and good image quality, but the TV's I've owned from them didn't last, and their support is terrible.

For Plasma, all are 600hz refresh rate, good brands are Panasonic and Samsung. Of the two I prefer Panasonic.