Wow, we have dug up an old......but excellent thread here. I love JohnnyApple's suggestion of The Right Stuff, one of my favourite films but I think I would eventually plump for The Ipcress File.
It would be hard to settle on one, I have a problem settling on 30, but it would have to be one of these three:
The Quiet Man (1952 with John Wayne)
Willy Wonka (1971 with Gene Wilder)
V for Vendetta (2005 with Natalie Portman)
I really do not know which I would go with.
The Scarlet Pimpernel...must be the version with Jane Seymour and Anthony Andrews. Great swashbuckling movie with adventure, romance, betrayal, integrity and honor.
Difficult to only go with one movie as there are so many good ones.