Which is better, Plasma TVs or LCD's with 120hz processors?

120 Hz is being pursued by manufacturers of LCD TV to compensate for the technical flaws of LCDs. 120Hz is capable of compensating for motion jitter and movie judder, but NO 120 Hz machine can remove all of the motion blur produced by an LCD TV. To completely remove motion blur will require a 240 Hz machine. Don't look for 240 Hz TVs for awhile since they have NOT been able to perfect 120 HZ yet. Movie and sports shots with panning & subject motion over whelm the 120 Hz co-processors and create pixilization artifacts. At times this pixilization can be worse than the ill they aim to correct.

Plasma TVs DO NOT need 120 Hz (as TV Guy has said) because they do not produce motion jitter and motion blur. Movie judder is a result of using the old refresh rates of 60 Hz while movies are filmed at 24 Hz. Cinema 3:2 pull-down techniques adopted to deal with this issue is the culprit. Plasma TVs exist that offer newer cinema modes that either work at either native 24 Hz frame rates or 120 Hz. But DO NOT infer that 120 Hz on plasma HDTVs is required to compensate for motion blur or judder.

Full motion on any HDTV will reduce the effective resolution of your TV. How much resolution is lost during full motion viewing is dependant upon the TV technology. Even with 120 Hz operation & 4 ms LCDs, the best LCD HDTV can only produce the equivalent of 450 vertical lines of resolution (down from 1080). Plasma TVs rate out at 900 equivalent lines of resolution. I see this when watching football. As the camera pans downfield with the play, a plasma TV is capable of presenting grass texture on screen. NO LCD HDTV can present anything that looks even remotely like grass texture in the same scenes. Plasma TVs are the best if you like action movies and sports.

Plasma DOES NOT NEED 120 Hz because the plasma phosphors are faster than LCD transistors.

120 Hz helps with film judder and some motion blur. I say plasma all the way - as long you don't use it to play games (image burn in concerns).

A 120Hz TV with 1080/24p input provides the smoothest motion for movies. It is definitely better in this respect than plasma, but for all other materials (TV, games) it doesn't make much difference. Interpolated frames (the extra frames between the 60Hz frames) do help smooth the appearance of pans and slow-moving objects. Newer plasmas are adopting 120Hz anyway.