resolution or AA, AF

[BenSkywalker]

anything above 40fps is blended together by human eye seamlessly.

Download FPSCompare and check it out for yourself. It sounds like you will be surprised at just how easy it is to see framerate differences closing in on 100FPS for the typical person.

 

[JBT]

Turn Shadow quality down to low it helps me ALOT in CSS and HL2 and really doesn't look much different.

The reason movies look okay at 24FPS is because they use motion blur.