Cute, bullshits galore this whole thread.
The human eye can easily notice a difference between both 30 and 60fps, and 60 and 120fps. Anyone saying anything else is either talking crap, or seriously need to have their eyes checked. That being said, the core component here is the monitor. If you got a standard monitor, it will display the image at 60hz, meaning that 60fps is the cap of useful fps. Anything over that is overrendering, seeing as how the monitor cant display any more. With a 120hz monitor that number climbs to 120fps.
Put 2 identical high end computers next to eachother, both with a 120fps cap. One connected to a 60hz monitor, and one connected to a 120hz monitor. You WILL see a massive difference.
For a PROPER AND SCIENTIFIC answer to the matter: http://amo.net/NT/02-21-01FPS.html
Read that and get educated, hopefully the lot of you will stop spewing this crap.