In most cases 30 fps works just fine. (anything slower getsto be very noticeable) When extreme speed is involved (like in racing) is where you will noticed the big differences between 30fps to 60fps.

 As far as the fps the eye can see isn't so clearly seen the brain converts an antalog signal to digital and create it's own snapshot frames. Thus there is a difference between what you eyes sees and what your brain sees.

60fps is very important for first person shooters, because it is easier to aim, predict where people will go, etc.
I also wish movies were shot at 60fps....anyone know why they still stick to the antiquated 24fps standard?

Soriku said: Didn't Krazy Ken want 120 FPS for the PS3? Wonder how that'll look (if it ever happens)

Meet someone that has a Radeon 3850 and Orange Box.

It depends a lot on the type of game.  Racing games especially benefit from a solid, consistent 60 fps, as do twitch FPS games.  Honestly though, even Super Mario Galaxy benefits massively from being locked at 60 fps, IMO.  You might not need the control granularity of 1/60 of a second, but I think it makes the game world feel more natural and alive.

Usually a solid 30 FPS at higher HDTV/monitor refresh rates (60-120 Hz) is sufficient. Motion blur can improve things as well as 60 FPS (solid or allowed to drop to solid 30 FPS during action packed scenes). The importance will differ from game to game.

Whats with everyone talking about eyes and FPS? You don't see in frames! The human eye works in fluid, constant vision.

P.S.  I play Quake 3 Arena and Quake II at 120+ FPS and it looks great especially the insanely high run speed in those games (especially Quake 3). 

 The eye is measured at 60fps, hence, people want games to run at 60fps.

 Ummm..... Last time I checked, Framerates having nothing to do with the time it takes for your mouse/keyboard to send info to your processor. You get that jerkiness at lower framerates because your computer has to compensate for how fast your trying to move, and how fast your frames are going by. I mean a game running at 500 fps, doesnt mean your reaction time is 5 times faster than that of a game at 100.

 Because scientists have found that our vision is the equivilent of around 60fps, thats why when you spin in circles things begin to blur, because your eye and brain cant capture the light fast enough to keep it clear and non blurred.