LCDs and CRTs are different tech. In a CRT, there is an electron beam that sweeps through lines on the screen. The electrons hit a phosphor film, exciting the phosphor atoms when then re-emit the energy as the light you see coming out of the CRT. Naturally, the beam doesn't stay there continually exciting that particularly pixel, it has to do the whole screen, so eventually that pixel stops glowing. But the beam comes back ever 1/60 second to "refresh" that pixel. So in effect, you get a flicker. Normally, this won't bother you too much, unless you are very sensitive or you watch it for hours on end or at close range or you are viewing the screen in a room with fluorescent lights. Those lights also flicker at 60 Hz, so there's an interference pattern set up.
On the other hand, and LCD is made up of pixels, there's a little dot for each bit of resolution (actually 3 dots - red, green and blue, sub-pixels) that act as little filter gates that let the light of the backlighting screen through or not. For red, they let the red component of the light through and the same for green and blue, which when mixed in the right proportions, give you a specific color. These gates are working continuously and the backlight is also on continuously (though it is a fluorescent as well - that's the 60 Hz - the back light screen spreads and blends the light from the tube pretty evenly so there's not a lot of effect) so they don't need "refreshing", they just change the intensity of the color light they let through. So, there's no flicker.
So, for the most part, Hz is meaningless on an LCD. The important factor on an LCD is response time, that's how fast a particular pixel can change from full off to full on. If that's not fast enough, you can get ghosting. This happens when a line of color passes across the pixel very quickly and it can't change color fast enough. Typical response times are around 25 ms to 45 ms. Ghosting seems to be a problem when the response time is greater than 30 to 40. It also depends on the size of the screen and its resolution, though not as much. That's basically a distance thing, the farther apart (either low resolution or large screen size) the pixels are, the longer time they have to change, however, that tends to make a grainy image. The higher the resolution, the faster the response times have to be though that can be offset some by screen size.
I do note that its not a good idea to change the Hz on a LCD, you can damage it and they are not cheap, generally around $400 to $500 plus labor to replace.