I have yet to see CASABLANCA or GONE WITH THE WIND so I cannot say much about those two.

I have some certainty about CITIZEN KANE but it's not the best although it has great potential. THE SEVENTH SEAL definitely is legit enough to be a #1 somewhere.

If Spielberg is on the list I would say CLOSE ENCOUNTERS OF THE THIRD KIND would be a better choice for some of his best work.