6) Avatar/Titanic
James Cameron does not do half measures. His two greatest claims to fame, Titanic in 1997 and Avatar in 2009, were intended to give new meaning to the concept of film epics, and their contributions to the technical world of filmmaking are significant, whether their storytelling happened to appeal to you or not.
Titanic took the emotional high stakes of young romance and combined it with the physical high stakes of the largest shipwreck in history, an ill-fated love story of the most epic proportion. It almost plays like two movies in one, and takes the time to develop both aspects of the story, both movies, to the fullest. What interest it may have lost for some during the courtship period it regains in a big way with one of the most dazzling special effects sequences at the time.
Avatar also strives for this depth of emotional resonance, but its science fiction angle makes the time spent exploring the world of Pandora pure pleasure. The story itself is almost peripheral to the immersive sensation that was unlike any movie to come before.
The fact that viewers flocked back to the theaters to watch Cameron’s films multiple times should indicate that they were more than willing to devote far more than a mere 3 hours experiencing these stories.