is the room well lit or dark?
If you can still find a plasma, they have (IMO) the best picture, color saturation, and the most natural refresh rate. They dont make many any more because of rules in california banning tvs that use more than a certain # of watts. They have better blacks than LCDs. the only problem with plasma is the screens are extremely shiny and you catch glare from even the smallest light.
I dont like like LEDs because i feel their color is washed out and the 240 refresh rates honestly ruin special effects. you can see how fake things look on certain movies. think pirates of the Caribbean 2. the big monster hinestly looks like a rubber suit on my father in laws TV, and i had a problem with lip sync for a while although i have gotten used to it. i just seemed like it was off for a long time until i got used to it (i had the same problem with 120 hz tvs too)
My opinion on LEDs aside, they have true black since there is no back light like on LCD and plasma. either the pixel is on or its off and if its off its true black. Thats not so important to me but certain film buffs deal with the color saturation because of that feature...
Samsung is my brand of choice. I just like their color the most and they are generally cheaper than sony for the same specs