Check out the video I posted earlier, says it all. Quake2 is the worst game for input lag I've played, but most games suffer a bit because they all too frequently put the user input at a lower priority to other things like AI, physics, etc.
QuakeII Input Lag Demo
Supreme Commander is a good example of the opposite where it is done correctly. That game can be utterly raping your machine (both cpu and gpu) but as soon as you hit escape the menu pops up and the mouse is smooth as butter and you have full control. This is how games should be.
The point I'm making is simply that you can have all the frames per second you like, but if the game is inherently laggy with its input then it's a waste of time optimising an excessive framerate for a competitive edge.
I'm so glad we're not in 1998 anymore.....

