I don't think motion blur has anything to do with it, except make the image look less sharp.
AFAIK anything above 30 fps it's basically wasted. You _may_ (or may not) tell the difference between 30 fps and 50 fps if you watch two animations side by side, one in 30 one in 50. But if you see one today and one tomorrow, even 20 fps will probably look just as smooth.
Moraelin -- the proud member of the Idiots' Guild