Of course this list is subjective. You could expand this list in 1000 different directions, based on genre, actors, directors, etc. Overall, I think this is a good comprehensive list. I was a little surprised I've seen as many as I have. I've added some new flicks to my queue, and some repeats too!
Just because, I'm going to attempt to see every movie on this list before the end of the year. I think there is only one musical here (Sound of Music). I hope I can make it through that...I hate musicals!
0-9
2001: A Space Odyssey (1968)
400 Blows (1959)
8 1/2 (1963)
A
The African Queen (1952)
Alien (1979)
All About Eve (1950)
Annie Hall (1977)
B
The Battle of Algiers (1967)
The Bicycle Thief (1948)
Blade Runner (1982)
Blow Up (1966)
Blue Velvet (1986)
Breathless (1960)
Bringing Up Baby (1938)
Sundance Kid
C
Chinatown (1974)
Citizen Kane (1941)
Dragon
D
Double Indemnity (1944)
Dr. Strangelove (1964)
E
The Exorcist (1973)
F
G
Grand Illusion (1938)
H
A Hard Day’s Night (1964)
I
In the Mood For Love (2001)
It Happened One Night (1934)
J
K
L
The Lady Eve (1941)
Lawrence of Arabia (1962)
M
M (1931)
The Maltese Falcon (1941)
Modern Times (1936)
Monty Python and the Holy Grail (1975)
N
Nosferatu (1922)
O
On the Waterfront (1954)
P
Paths of Glory (1958)
Princess Mononoke (1999)
R
Raise the Red Lantern (1992)
Rashomon (1951)
S
Schindler’s List (1993)
The Searchers (1956)
Seven Samurai (1954)
The Sound of Music (1965)
Sunset Blvd. (1950)
T
The Third Man (1949)
This is Spinal Tap (1984)
U
V
W
Wild Strawberries (1957)
Wings of Desire (1988)
Women On the Verge of Nervous Breakdown (1988)
The World of Apu (1959)