not doing this one properly but i'll throw out an unordered and boringly obvious top 5 with mostly old reviews:
Night of the Living Dead
candidate for most ahead-of-its-time movie ever.
2001: A Space Odyssey
i still get goosebumps when the jogging starts, and they pretty much stick around until HAL's demise. the opening few minutes stand as the benchmark for landscape cinematography, and the glacial pacing is hypnotic to a fault. obviously the film is about transcendence, about instilling in the audience a sense of the vast possibility in our species' future (analogising it with our progression from ape form), but this is tempered by the fact that such possibilities are inevitably incomprehensible. that doesn't faze kubrick however, so intent is he on forcing a confrontation with The Unknown; the specifics of that concept are ours to project, but kubrick is there to provide the space upon which we may project them, and the impetus to do so. it's clear, in turn, that the monolith is kubrick's stand-in, intending to inspire a kind of awakening within us, trigger the next evolutionary leap.
perhaps he in some way succeeded, and we have begun the process of transcending the humankind that first encountered 2001 45 years ago; the film's ability to evoke wonder and awe is waning a little precisely because we're approaching the kind of information-overloaded, technocratic society kubrick once predicted. in the film, humanity's attempt to transcend via technology is botched, and perhaps the same is happening now; but it is that failure which sparks bowman's final transformation into the Star Child. the future remains ahead of us, but either way, 2001 is a stubbornly audiovisual film which insists upon the capacity of cinema at its purest to encapsulate--and in doing so, perhaps even influence--the direction of our entire species. there exists no greater affirmation of the power of this artistic medium.
Once Upon a Time in the West
civilisation's railroad is creeping up over the hills, and the old west totters on the brink of extinction. once upon a time... is the dream of one final, glorious swansong, where mythical anti-heroes fight it out across a sweeping backdrop, in a world where those who think with their heads are about to stop losing. left alive is a lady of civilisation, basking in the benefits of progress, and a hero of the old school, purpose extinguished, about to fade into obscurity forever.
Faces
a film that can be accused of inconsistency, of hysterical melodrama, of failing to be as real as it might seem to be trying to be -- particularly when anyone aside from marlin, forst and the inimitable, spellbinding gena rowlands are having to do the work -- but i don't think any of these characteristics are hugely problematic to cassavetes' vision. yes, this is a movie which revels in the mess of real life, riotously exaggerated, as opposed to both your schematic hollywood fictions and neo-realism's brand of deromanticised restraint. but simultaneously, it's also examining precisely what constitutes "real life" and real human connections; it's a film about "mechanical men" and women which reveals flashes of real, naked vulnerability beneath layers of artifice, and so for the film itself to tonally mirror this chaotic swaying between different levels of said artifice is entirely fitting. these characters are always "performing", and not always well, so the actors and their lines don't necessarily need to convince either. cassavetes pioneered and perfected the shakycam close-up long before it became an easy shorthand for "realism", and used it to much more complex effect; his camerawork isn't a mere indicator of immediacy but a search, a quest for the real, mushing up into his characters' faces and careering around the clutter of their homes as though desperate not to miss any rare glimpse of their souls. and even at this early stage of his career, even using this technique, he still stumbles onto sudden shots of striking compositional import without it ever seeming contrived.
Rosemary's Baby
i don't remember it too well now but probably polanski's best, which is to say it's a top tier horror classic. a fucking tough watch in the best way.