A fantastic response with some great films and arguments.

A few comments:

Twelve O'Clock High - yes, that one ought to have had an honourable mention in retrospect.

Lawrence of Arabia - I revere this film (as you can see from this recent article) but decided to go with The Bridge on the River Kwai for this list instead, out of the two possible David Lean choices.

Ran - Great shout. One of Kurosawa's best, and probably the last great film he ever made.

Henry V - Both the Branagh and Olivier versions are terrific.

Downfall - Another interesting choice. I should have considered that one too, or at least given it an honourable mention.