Lots of good recommendations so far, so as a connoisseur of 70’s films, allow me to shit up the thread with some wild cards:
Prime Cut - Gene Hackman as a Kansas farm gangster named Mary Anne goes up against Chicago gangster Lee Marvin. The leads alone are enough to make it a must see, but there’s so many bonkers scenes. Sissy Spacek as a drugged up sex slave being auctioned from a cattle pen. A car is attacked by a wheat thresher (as well as a pitchfork). 70’s filmaking at its finest. Directed by Michael Ritchie, who would go on to do another couple of 70’s must sees - Smile and The Bad News Bears
The Driver - Noir meets the car chase film. Nice barebones crime flick about a getaway driver, played by Ryan O’Neal, who does a surprisingly god job with it, considering he was known at the time for comedies and romance movies. Car chases are really well done, too. Second film directed by Walter Hill, who started a killer run with his first, Hard Times - a bareknuckle illegal boxing flick, with Charles Bronson and James Coburn, and would go on to make The Warriors, The Long Riders, Southern Comfort, and 48 Hours. All solid movies, even if the last few are technically 80’s films.
Juggernaut - Fuck Titanic and Poseidon Adventure. This is the best ocean liner disaster movie, IMO. Mostly because it spends the whole time taking the piss out of disaster movies. Richard Harris is a leader of a bomb squad, who paratroop onto an trans-Atlantic ocean liner to try and remove a bunch of bombs planted by an Irish terrorist. Harris’ bomb-diffusing prep consists primarily of drinking, and so…things don’t go very well. Omar Sharif, Ian Holm, and Anthony Hopkins fill out the cast, with Roy Kinnear showing us who the unsung victims of ocean liner disasters really are - the Entertainment Directors. Directed by Richard Lester.
Sorcerer - Wages of Fear remade by William Friedkin. One of the few instances where I like the remake better. Captured the desperation of the protagonist political-criminals living in exile and the futility of transporting past-its-sell-date dynamite across a South American jungle better I thought.
Emperor of the North - Lee Marvin plays a depression-era hobo, who is a hero to all of Hoboland, and is so named, “A-Number-One”, mainly for his mad train-hopping skills. His latest act of derring-do is to ride a specific train, whose conductor (Ernest Borgnine) is a fucking psychopath, who takes great delight in dispatching stowaways on his train with hammers, rope darts made with coupler pins, and whatever else he can dredge up. I mean, who the fuck would make a movie about this nowadays? Directed by Robert Aldrich, who also made The Dirty Dozen, The Grissom Gang, and Whatever Happened to Baby Jane.
Brewster McCloud - A teenager (Bud Cort) who lives in the basement of the Astrodome wants to make a set of wings and fly. Also Rene Auberjonois plays an ornithologist who slowly transforms into a bird. It’s…too weird to really describe, but it’s my favorite Altman movie.
Other solid 70’s films I haven’t seen named yet:
Fantastic Planet
Charley Varrick
The Shootist
Day of the Jackal
The Jerk
Mr. Majestyk
Two-Lane Blacktop
The Last Valley
Watership Down
Bring Me the Head of Alfredo Garcia
