that the greatest film of all time is Citizen Kane. Good film yes but greatest?
Anyway people's tastes vary so much in this respect. I mean I even heard that Sound of Music was up there in the lists. Come on, I would rather walk around with a bucket on my head than watch the S of M. If you want musicals Some Like it Hot has to be up there with the greatest
To me a good film is one that you want to watch again. The Sixth Sense does it for me. One with a real twist to the ending.
What floats your boat?