About a month after first seeing this list, I can now say that I've seen 97 of the 100 movies listed. The ones I haven't seen are movies I couldn't find. Of the 16,186 people that took this quiz, 97 puts me in the top 1%.
I thought I'd compliment this list/quiz with a list of my own. Here is what I came up with.
A. The Movies on this List that are Unquestionably Great, and Which Should be Seen by Everyone, Everywhere
1. The Godfather (1972)
2. The Godfather Part II (1974)
3. Apocalypse Now (1979)
4. One Flew Over the Cuckoo's Nest (1975)
5. Jaws (1975)
6. Taxi Driver (1976)
7. Rocky (1976)
8. Patton (1970)
9. Close Encounters of the Third Kind (1977)
10. The Exorcist (1973)
11. The French Connection (1971)
12. Aguirre: the Wrath of God (1972)
13. Monty Python and the Holy Grail (1975)
14. Deliverance (1972)
15. Barry Lyndon (1975)
16. Alien (1979)
17. The Conversation (1974)
18. The Last Picture Show (1971)
19. All the President's Men (1976)
20. Dirty Harry (1971)
21. Coming Home (1978)
22. Carrie (1976)
23. Kramer vs. Kramer (1979)
24. All That Jazz (1979)
25. Amarcord (1973)
26. Shampoo (1975)
27. A Woman Under the Influence (1974)
28. The Man Who Would Be King (1975)
29. The Towering Inferno (1974)
30. Klute (1971)
31. Sunday Bloody Sunday (1971)
32. Save the Tiger (1973)
33. Lenny (1974)
34. Norma Rae (1979)
35. Superman (1978)
36. Enter the Dragon (1973)
Notes: Many of the above movies would qualify as "greatest of all time" - not just greatest of the 70s. The Godfather Parts I and II, Apocalypse Now, and every other movie up until #24 is, in my opinion, classic.
Around #25 or so is where I'd start describing movies as just "greatest of the 70s." They're excellent movies, but they belong more to the decade that produced them. Shampoo and The Towering Inferno in particular, but even movies like Superman and Amarcord have a charm half traceable to their quality, half traceable to the sense of nostalgia they're apt to engender.
Of all these movies, All That Jazz is the one that really blew my mind. It is dismissed by some critics as pretentious and unwatchable, but I loved it. If you're looking for a movie where the director went all-in, All That Jazz is the movie for you.
B. The Movies On This List That Are Watchable, but Definitely Not Great
37. Chinatown (1974)
38. A Clockwork Orange (1971)
39. Star Wars (1977)
40. The Deer Hunter (1978)
41. Network (1976)
42. American Graffiti (1973)
43. Mean Streets (1973)
44. Serpico (1973)
45. Blazing Saddles (1974)
46. Young Frankenstein (1974)
47. Animal House (1978)
48. The Sting (1973)
49. Dog Day Afternoon (1975)
50. Five Easy Pieces (1970)
51. Nashville (1975)
52. Saturday Night Fever (1977)
53. McCabe and Mrs. Miller (1971)
54. Badlands (1973)
55. The Conformist (1970)
56. Willie Wonka and the Chocolate Factory (1971)
57. The Texas Chainsaw Massacre (1974)
58. Life of Brian (1979)
59. Days of Heaven (1978)
60. Alice Doesn't Live Here Anymore (1974)
61. Bound for Glory (1976)
62. The Hospital (1971)
63. The Last Detail (1973)
64. The Sunshine Boys (1975)
65. Cabaret (1972)
66. Breaking Away (1979)
67. The Candidate (1972)
68. The Poseidon Adventure (1972)
69. The Goodbye Girl (1977)
70. Midnight Express (1978)
71. A Bridge Too Far (1977)
72. Sounder (1972)
Notes: I wanted to put Chinatown in the "Massively Overrated" category, but it's definitely more watchable than the other films there. Not great, but good. Ditto for Clockwork Orange and the Deer Hunter. Yeah, they're "great" movies, but have you tried to sit through them lately?
Despite my undying love for Network, I couldn't bring myself to place it in the "Unquestionably Great" category. It has definite flaws, though these flaws make it - in my eyes at least - more endearing.
Nashville is a movie that critics love, and while I liked it I can't say that it bowled me over. It seems more like an interesting experiment than an actual movie. Some great scenes there, but I can't say that they add up to a satisfying whole.
The Conformist is a wonderful looking film, but what about the story? What about the characters? Certainly worth a look on artistic grounds, but it lacks the dramatic weight that a truly classic movie ought to have.
C. The Movies on this List That Are Weird Enough to be Somewhat Interesting
73. The Man Who Fell to Earth (1976)
74. Tommy (1975)
75. Last Tango in Paris (1972)
76. The Last Wave (1977)
77. Macbeth (1971)
78. Julia (1977)
79. Being There (1979)
Notes: None of these movies are especially entertaining, but if you're in the mood for something weird you might like them.
The stories of how these movies were made are also interesting in and of themselves. The Man Who Fell to Earth? Bowie was snorting his weight in cocaine - on a daily basis. Last Tango in Paris? A beautiful female lead, and decades of rape allegations. Macbeth? Made just after Polanski's pregnant wife was murdered by the Manson Family.
And on, and on, and on...
D. The Movies on this List That Are Massively Overrated
80. Annie Hall (1977)
81. M*A*S*H (1970)
82. The Rocky Horror Picture Show (1975)
83. Halloween (1978)
84. Grease (1978)
85. Manhattan (1979)
86. Fiddler on the Roof (1971)
87. Bananas (1971)
88. Sleeper (1973)
89. Marathon Man (1976)
90. The Discreet Charm of the Bourgeosie (1972)
91. Don't Look Now (1973)
92. A Touch of Class (1973)
93. Heaven Can Wait (1978)
Notes: I fucking hate Woody Allen. It has nothing to do with any crimes he may or may not have committed. I just hate every single film he's ever directed, starred in, or had anything to do with.
Halloween is a lot like A Clockwork Orange. People gush over it, but the people doing the gushing probably haven't seen it in a while. Even during the 70s there were much better horror movies.
E. The Movies on This List That are Just BAD
93. The Ruling Class (1972)
94. The Way We Were (1973)
Notes: I can't figure out why someone put The Ruling Class on this list. It never won any awards, it was never particularly favored by critics, and it is CRUSHINGLY BORING. I made it about halfway through and gave up.
The Way We Were was a calculated attempt to make Barbara Streisand into (more of) a star. In this regard it could be considered an inferior version of A Star is Born, which at least featured a male lead that Streisand had some kind of chemistry with. The Way We Were just makes you feel sorry for Robert Redford.
F. The Movies on This List That Were So Depressing I'm Sorry I Watched Them
95. Cries and Whispers (1972)
96. Scenes from a Marriage (1973)
Notes: Ingmar Bergman... are Swedish people really like that? I certainly hope not. I found Scenes from a Marriage slightly easier to sit through, but Cries and Whispers, which features a woman slowly dying of an agonizing disease, might have been more agonizing than the disease featured in the movie.
G. The Three Movies on this List I Couldn't Find
98. Il Giardino del Finzi-Contini ("The Garden of the Finzi-Continis") (1970)
99. Seven Beauties (1975)
100. Day for Night ("La Nuit Americaine") (1973)
Notes: The first two of these movies, like The Conformist and Amarcord, are Italian films about fascism. Day for Night is a film by Truffaut. All won or were nominated for foreign-language Academy Awards.
H. Movies That Should Have Been on this List, But Weren't
101. Diamonds are Forever (1971)
102. THX 1138 (1971)
103. The Omega Man (1971)
104. Jeremiah Johnson (1972)
105. Pink Flamingos (1972)
106. Fist of Fury (1972)
107. Pink Floyd: Live at Pompeii (1972)
108. Fantastic Planet (1973)
109. High Plains Drifter (1973)
110. Female Trouble (1974)
111. Zardoz (1974)
112. Thunderbolt and Lightfoot (1974)
113. Shivers (a.k.a. "They Came From Within") (1975)
114. Logan's Run (1976)
115. Smokey and the Bandit (1977)
116. Oh, God! (1977)
117. The Spy Who Loved Me (1977)
118. Desperate Living (1977)
119. Suspiria (1977)
120. Every Which Way But Loose (1978)
121. Dawn of the Dead (1978)
122. Star Trek: the Motion Picture (1979)
123. The Brood (1979)
Notes: I've already discussed the above movies in other entries about the 70s. I hereby refer you to Bond: the 1970s, Movies of the Early 70s, Movies of the Late 70s, and The 1970s: A Few More Films.