If I wanted to show three movies that 'well represented' what a movie was all about...I would choose:
Battles & wars: Braveheart
Animal adventure: Fly Away Home ( I know, I know...not a classic film...but the story...the music, the way I felt at the end...)
Love Story: Return to Me
Drama: Fried Green Tomatoes I know this is four but those are my favs.