I guess eyes do see more than 60fps, but I'm not sure. But at least you can see a big difference in 60hz and 85hz.

After 85hz, I guess, you don't see a big difference, if any.
Originally posted by CP5670
I think the limit is 71 or something for most people, but it really gets on my nerves when things start to go below 60.
(I can make out the difference, somehow) As an avid online gamer (where framerate really matters), I would be ready to have everything drawn as untextured vector line polygons if that would ensure that the framerate stays high.
For many games, 40fps is usually enough for me. I think I would see a difference in 40fps and 60fps even in those games, but my computer is crap and doesn't have even those frames. But in fast-paced game like Quake 3, 40 fps is certainly not enough. 50fps is ok, and 60fps is enough. If you have 60fps the whole time, I guess it would be enough. But if it drops from 100 to 60, then I guess that most people would see a difference.
I agree that in multiplayer you should have good fps over visual quality, but in single player it's not so important. I still, however, prefer good frames over visual quality.
