i sit here for the umpteenth time watching one of my all-time favorites: The Day the Earth Stood Still.
i have it on dvd.
i’ve seen it more times than i can count.
i watch it often.
is there a more perfect sci fi film?
name your poison! 
I liked Blade Runner.
But The Day the Earth Stood Still is wonderful, too.
Prince of Space
Game over 
good choice. you’ve seen the director’s cut of course?
To me, what makes a sci-fi film great is how believable the “fi” part is. I think “The Day the Earth Stood Still” is a great movie, but adheres to too many cliche’s (flying saucer, invincible robot, etc.).
I nominate:
“Contact” - for depicting not only a realistic first contact, but also the reaction of the world to such an event.
“Andromeda Strain” - a menacing alien doesn’t have to have a long, silvery head.
To be honest, it’s hard to beat Star Wars (1977) for this one. I’m not a fanboy by any stretch of the imagination, but it really was one of those films whose release created a dividing line between “before” and “after.” It truly changed how audiences and the industry approached the movies, for good and ill.
Any love for 12 Monkeys? Just about every time travel trope was worked into that one.
I’m one of the few (the proud few) who really likes Gattaca.
Star Wars is space opera, not science fiction in the strictest sense of the term. It’s a very watchable movie (and yes, it, along with Jaws and Raiders of the Lost Ark did influence the movie industry toward producing summer blockbuster films and broad-scale marketing), but great science fiction it is not. Indeed, it is a pastiche of war movies, Westerns, epic fantasy, and samurai films and stories. The Empire Strikes Back is by all objective measures a much better and nuanced film, though still more in the realm of space opera rather than science fiction.
For real science fiction, I’m going to have to go with Blade Runner (despite some problems with the actual characterization) as being thematically deeper, essentially a cyberpunk-esque adaptation of Paradise Lost. 2001: A Space Odyssey is a close second (although I recognize that the sparse plot is off-putting for many). Gilliam’s 12 Monkeys is a consistant and intelligent approach to time travel stories, something I could imagine coming from the pen of Frederick Pohl (Brazil, strictly speaking, isn’t science fiction, lacking as it does any significiant technological elements), and Aliens is a good straightforward action/sci-fi movie with humanistic elements, as is Star Trek II: The Wrath of Khan. (Cameron’s The Abyss is up there as well, as long as you turn it off before the aliens rescue Ed Harris.) As far as classical science fiction, Fritz Lang’s Metropolis and Weine’s The Cabinet of Dr. Caligari stand out, as does Forbidden Planet and the Don Siegel directed Invasion of the Body Snatchers.
As much as I wanted to like Minority Report, AI: Artificial Intelligence, Contact, et cetera, the logical and structural problems bothered me too much to rate them highly. They Live and The Thing, both John Carpenter B-movies, had more to recommend them in concept, and City of Lost Children and Delicatessen are at least visually stunning sci-fi-esque fairy tails that are inimitable.
In general, feature cinema doesn’t do to well with science fiction; most “real” sci-fi tends to be either to cereberal or too philosophical for film. The original “The Twilight Zone” has more and better science fiction stories than can be found in most film, primarily because the brevity of the episodes (and no doubt low cost of filming) is better suited to conceptual science fiction as opposed to action-oriented space opera.
Stranger
**2001: A Space Odyssey ** without question, although that’s really more science-fact than science-fiction.
I’d say dune was my favourite sci-fi movie, if maybe not the best. It’s very flawed in basic cinema terms but it excels in other ways. It does an exceptional job at evoking a true otherworldly atmosphere, real sci-fi rather than a cops and robbers film transplanted into outer space as is often the case. There is some mystery to the film, it doesn’t spell everything out in capital letters to the audience. It’s a great example of world-building in the cinema, something very difficult to do.
Many films that stray from the company line are ‘interesting’, but dune is more than that. It has to be counted as a major Sci-Fi film on originality alone.
I somehow managed to buy the film three times, so I must like it :smack:
I liked Gattacca, it felt more plausible somehow, perhaps a bit more of the science-fact noted above. Somehow I missed Sage Rat’s approval of it too until previewing my post.
*2001: A Space Odyssey * - a beautiful, timeless and strangely human film. I disagree that Star Wars is the before and asfter line - 2001 is one of the defining moments of any perspective on film history. A masterwork and the greatest science and or fiction film ever made.
This is a bit pointless since Stranger has posted and should probably have the last word 
and has already mentioned most of my choices Forbidden Planet/Aliens/Blade Runner.
How about Dark Star? For a touch of “realism”. I’d imagine real space adventure would be much more like this than Star Wars.
For heaven’s sake no one mention Starship Tr. . . Oops.
I remember now what I forgot to post, Solaris, another film where the aliens aren’t big bug eyed monsters.
Lang’s Metropolis.
Silent Running with Bruce Dern
I think 2001: A Space Odyssey inspired many later films.
The ideas of the bone turning into a space station; playing chess against an intelligent computer; exercising right round the spaceship; taking a long time to arrive in space - these were all impressive.
I really like Gattaca, too. And that’s despite being aware of the absurdity of the premise and strongly disagreeing with the moral of the story and thinking that the hero’s action were extremely unethical. I’m used to having all those issues when reading SF, especially SF from before the '70s. But Gattaca also excels in the same way that a lot of that older SF does.
Not with a masterpiece such as Battlefield Earth that clearly overwhelms it.