From an article about the new Sony BRAVIA line of LCD High Def TVs written by HDGuru - 'Sony will be announcing 120 hz flat LCD panel today. The 120hz rate will greatly reduce the motion blur that occurs with all 60hz LCD panels.'
http://www.hdguru.com/ scroll down to Feb 27th if you wanna read the whole article.
At the showroom floor I was looking at different models. Samsung has a high Hz model as well. High speed visuals look perfectly crisp throughout. No motion blur whatsoever. It's very telling when you watch them side by side.
Hm, interesting.
However, again, this is about TVs.
Also, since the input signal is 60fps at best (!!!), those 120Hz mean it has to repeat every image twice.
It will then do some other post-processing to enhance (at least that's what it is supposed to...) image quality.
All this does not happen on a regular PC LCD.
Plus, the high resolution means you will hit the limits of the DVI connection so unless you run at 1024*768 or a similar lower res, you will not be able to set the refresh rate above 60Hz.
Hence, for PC LCDs, it is more important they feature a short response time (ususally ~8ms, anything less is pure marketing BS!) than a rediculously high refresh rate (that your GFX card cannot deliver anyway) for a non-ghosted image.
Speaking of response times, there's different values you need to look at.
Firstly, it is composed of rise and fall times (eg how long it takes a pixel to get from black to white and then back to black).
These should be about even because if not, the short time of the one will be spoilt by the long time of the other.
Also, it's important to look at the grey-to-grey switch times. These should not be too far away from the white-black-white times.
A display with overdrive can help a lot here, but it may output the image a bit postponed due to the necessarily post-processing (yes, this is similar to the LCD TV and also another reason why those aren't really suited for any action-related gaming!).
All in all, it's never really simple and the specs listed at the shop probabaly only tell half the truth.
Best is to take a close look at the manufacturer specs on their website, however, you need to know what each means in order to read them "properly".