i believe movies are made at 24fps, and cartoons at about 12-18fps, to give you an idea of what your eyes seen

higher fps will just make all the movements smoother, and softer to the eye. And as was said, fps varies alot depending on what you do. Anyone can get 60fps when staring at a textured wall in full screen, but the fps dips when flying, using spells etc

ask 5 DK to do their aoe spells in dalaran and see how much fps you get there as a benchmark.
I never found out mine, i usually need to relog when it happens