What determines the quality of a (gulp) great screenplay?

[Sameguy]

Recently I came across a list of the top 100 films of all time and honestly I was surprised to learn that the films which I really expected to top the list were not even in the on it. I believe every script that ever gets to be made into a film must have great characters, a high concept story and tight wriitng or at least most of them do, but though all those three basics count to the commercial successs of a film what really does make some scripts far much better than others?

[claudie]

I'd say the story is first and foremost.
Well crafted story that doesn't leave any holes or gaps and has a few twists and surprises.
I'd put in this category "The Sixth Sense" and ... geez my mind went blank...
I don't always agree with those "lists" as to which were great.
What were you expecting to be on the list that wasn't?