My suggestion: once you have your movie list, divide it by year so you can also see the development of film. Like you have the silent films, then there's a little spurt of musicals when sound becomes available, that kind of thing. You can also see how historical events are reflected in the movies, either by escaping or engaging in what's going on.

And even if no one recommends them here, throw in a few of the films that redefined film, genres or cinematography - if you watch a bunch of early movies first, you can really see how films like Metropolis or Citizen Cane affected the films that came after them, but you're only really going to notice it if you're watching your film list chronologically.