Totally agreed, once you reach a certain framerate you will not be able to distinguish the difference. I am absolutely positive if you played a game at 50FPS and 100FPS and were not aware of the framerate, you wouldn't mention any difference in choppiness.
I believe once you get under 30 FPS you might start to notice a bit of choppiness, but once you are over 40 there is no freaking difference. It's all about psychology, you think you can notice a difference when you actually know there is a difference, but if there was no way of outputing framerate anything above 30 would look exactly the same to you.