Soylent Green gets my vote. “Soylent Green-—is people!!” For just pure awesome factor at the time, though, on the big screen, nothing tops 2001, A Space Odyssey. It didn’t have the political themes in it, but it was spectacular on so many levels, for its time. “What.. are.. you.. doing...Dave?”
Gads, can you imagine. I popped in a dvd of 2001 for my two 18yr old nephews who were visiting for a while, they couldn’t make it past the Blue Danube before losing interest.
That was the first movie I saw alone. I was about 12 (it was another era), and I saw it in one of the old school Cinema movie houses on a HUUUUUGE screen.
Needless to say, it left quite an impression.
2001, like 1984 and Brave New World, are only growing in importance as time passes.
As for the latter two, they are more science prophesy than science fiction.
Rendezvous with Rama, by Arthur C Clarke is another one that was stunning in the prophetic sense.
Harrison Bergeron, by Vonnegut, is another in that genre. He also wrote Cat’s Cradle, where if you consider the modern computer virus, could be considered prophetic.
Simply equate money with water in that book and you are there. Ice-9 froze all the water. A virus might do the same to the money. Target would probably agree with this notion.