We've all heard the good news about Blade Runner, Alien and Avatar. I'm tossing out a list of what I think are worthwhile unsung SF flicks, in no particular order - rate and share your thoughts with the rest of us!
Serious fare with serious actors, who don't act particularly well. It's not brilliant, but it does manage to confront a possible dark future while conveying an effective message about the problems of any society based on a rigidly determined class structure.
Prepare to have your mind blown. This is a deeply disturbing piece of cinema - the relentless transformation of a man into a scrap-metal cyborg at his own delusional choosing. Not for those seeking linear plot or engaging dialogue.
Miyazake's best film before "Princess Mononoke" brought him greater visibility in the U.S. The coloring is gorgeous, and the plants and animals prefigure the imagery in "Mononoke". It's also got aerial dogfights!
This is just another monster movie, but David Twohy made a brilliant casting decision when he picked Vin Diesel for his dark hero. He managed to capture just enough of the horror of "Alien" (can't see what's coming to kill you...). There are some glaring logical lapses, but it's still a good ride.