I personally think it would be more valid to compare Koji Kondo to John Williams than Nobuo Uematsu. At least in terms of popularity. I mean, just about everyone knows the Super Mario Bros. theme, at least they'd recognize it if you walked down the street humming it. I would say that less than 1 in 5 people would recognize, say the Final Fantasy theme if you were humming it as you walked down the street.
"So Brak, is that Polish? Or... no I suppose it wouldn't be."
--Mike Nelson- MST3K: the Movie