I would say I need to choose one from each genre. But, going by to OP rules...

STAR WARS. Cinema is, above all else, popular entertainment. SW would provide future film makers with the greatest material from the Epic, Historical Drama, Adventure, Fantasy, Sci-Fi, Western, and War Movie genres with some Comedy, Slasher, and Monster Movie elements to boot.

For Best Movie To Influence Popular Entertainment: STAR WARS

For Best Movie With A Message: 1984

For Best Movie Speaking To The Human Condition: GROUNDHOG'S DAY (with an Honorable Mention to BEDAZZLED)