About ancient sci-fi before of CGI who still stands, I agree about Metropolis, you would not say that's 1927, that's masterpiece, but everyone knows and agrees on that.
I'm not impressed by horror, and action is ok up to a certain degree... look Alien and The Thing, 95% of movie "nothing happens" and this is way more deep and scary. About 2001 a space odissey there 99.9% of movie nothing happens, it requires really a monk receptive status of mind, but it is rewarding (and tripping visuals, for who's into '60's).
However if you want to try even more anti-hollywood sci-fi, there's the russian stuff by Andrey Tarkovskiy, the original Solyaris 1972:
http://www.imdb.com/title/tt0069293/
Note that in some versions they've cut the initial scenes with hypnotic car driving around tokyo and that's a crime, since you need watch driving in tokyo with basic electronic bzzzzzzzzz in background for some minutes to get into the thing. Can't skip or fast forward russian sci-fi!
But the real final mind trip of pure sci-fi (I say pure since no any apparent sci-fi, no aliens, space or technology, no action, nothing!), complete opposite of hollywood, it is Stalker, 1979:
http://www.imdb.com/title/tt0079944/
Underrated as ranked just #214 with 8.1 vote, pretty unknown to the masses, Stalker it could be used as an subtle IQ + drug test, try it while watching those incredibly long scenes of water and grass waving..., or listen the talking.
After watch Stalker, re-watch the famous Blade Runner piece (guess who inspired from): "I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion.", basically stalker is a whole movie like that piece, lots epic philosophical blah blah, water or rain or grass on screen for hours like you gone fishing, and electro wave sounds, made in soviet ruins with 20 dollar budget. Still unparalleled on its genre.