On a 120 Hz LCD display, half of the information is "interpolated" to fill in an artificial frame in between each real frame by a chip in the TV, that's why they look like a documentary or something. As was mentioned, the signal is currently 60 Hz.

Lots of people like that look. I prefer a plasma as it remains more true to the source, higher contrast ratio, faster response, etc. Per inch of display, they are also considerably more affordable.