the game always depends, because i can handle most games on thier highest graphics, but for some reason my computer cannot handle moving shadowing that isnt from the main character or the character im playing, even smoke will do it.... so i set the settings to medium
example of such games: assassin's creed(i had a bad fan at the time, harmed my harddrive, might be able to play it better), BC2 (yep yep, medium) and other games with MASSIVE land on the screen at once (with the graphics on highest anyway)
Poll could/shoul've been specified more.
Gonna go out on a limb and say that most of the people who replied mostly play Source based games, which you can basically run with the highest settings with a toaster.