This is a mix of suggestions including established classics and films I believe are important. If you want to see how much they cost on UK Amazon, click on the links. Comments about the list are welcome.
Cabiria (Italy, Giovanni Pastrone)
1915
The Birth of a Nation (DW Griffith)
1916
Intolerance (DW Griffith)
Les Vampires (France, Louis Feuillade)
The Cabinet of Dr Caligari (Germany, Robert Weine)
The Golem (Germany, Paul Wegener)
1921
The Kid (Charles Chaplin)
1924
The Iron Horse (John Ford)
The Last Laugh (Germany, FW Murnau)
1925
Battleship Potemkin (USSR, Sergei Eisenstein)
The Gold Rush (Charles Chaplin)
Strike (USSR, Sergei Eisenstein)
1926
The Lodger (UK, Alfred Hitchcock)
Metropolis (Germany, Fritz Lang)
Mother (USSR, VI Pudovkin)
Napoleon (France, Abel Gance)
1927
Berlin Symphony of a City (Germany, Walter Ruttman)
The Crowd (King Vidor)
The General (Buster Keaton and Clyde Bruckman)
The Man with a Movie Camera (USSR, Dziga Vertov)
The Passion of Joan of Arc (Carl Theodore Dreyer)
Sunrise – A Song of Two Humans (FW Murnau)
1928
Asphalt (Germany, Joe May)
October (USSR, Sergei Eisenstein)
The Wind (Victor Sjostrom)
1929
Blackmail (UK, Alfred Hitchock)
Un chien andalou (France, Luis Bunuel)
Pandora’s Box (Germany, Georg Pabst)
1930
All Quiet on the Western Front (Lewis Milestone)
The Blue Angel (Germany, Josef von Sternberg)
City Lights (Charles Chaplin)
1931
M (Germany, Fritz Lang)
The Public Enemy (William Wellman)
1932
Liebelei (Germany, Max Ophuls)
1933
Duck Soup (Leo McCarey) featuring the Marx Brothers
Sons of the Desert (Lewis Seiler) feat. Laurel and Hardy
1934
L’Atalante (France, Jean Vigo)
It Happened One Night (Frank Capra)
It’s a Gift (Norman Z McLeod) featuring WC Fields
Song of Ceylon (UK, Basil Wright)
1935
Le Crime de Monsieur Lange (France, Jean Renoir)
Sylvia Scarlett (George Cukor)
The Thirty-Nine Steps (UK, Alfred Hitchcock)
1936
Fury (Fritz Lang)
Night Mail (UK, Harry Watt and Basil Wright)
The Only Son (Hitori Musuko, Japan, Yaujiro Ozu)
Modern Times (Charles Chaplin)
Partie de Campagne (France, Jean Renoir)
People of France (La Bi Est a Nous, France, Jean Renoir et.
al.)
Swing Time (George Stevens) featuring Fred Astaire
1937
Dead End (William Wyler)
The Grand Illusion (France, Jean Renoir)
Oh, Mr Porter! (UK, Marcel Varnel) featuring Will Hay
Pepe le moko (France, Julien Duvivier)
Stella Dallas (King Vidor)
1938
Bringing Up Baby (Howard Hawks)
Hotel du Nord (France, Marcel Carne)
Daybreak (Le Jour se Leve, France, Marcel Carne)
Gone With the Wind (Victor Fleming)
His Girl Friday (Howard Hawks)
Mr Smith Goes to Washington (Frank Capra)
The Rules of the Game (La Regle du Jeu France, Jean Renoir)
Snow White and the Seven Dwarfs (David Hand)
Stagecoach (John Ford)
The Story of the Last Chrysanthemums (Zzangiku Monogatari,
Japan, Kenji Mizoguchi)
The Wizard of Oz (Victor Fleming)
1940
The Grapes of Wrath (John Ford)
The Great Dictator (Charles Chaplin)
1941
Citizen Kane (Orson Welles)
The Maltese Falcon (John Huston)
Sullivan’s Travels (Preston Sturges)
Suspicion (Alfred Hitchcock)
1942
Casablanca (Michael Curtiz)
Cat People (Jacques Tourneur)
The Magnificent Ambersons (Orson Welles)
Ossessione (Italy, Luchino Visconti)
The Road to Heaven (Himlaspelet, Sweden, Alf Sjoberg)
1943
Day of Wrath (Vredens dag, Denmark, Carl Theodor Dreyer)
The Life and Death of Colonel Blimp (UK, Michael Powell and Emeric Pressburger)
Lumiere d’Ete (France, Jean Gremillon)
Meshes of an Afternoon (Maya Deren)
Millions Like Us (UK, Frank Launder and Sidney Gilliat)
Shadow of a Doubt (Alfred Hitchcock)
This Land is Mine (Jean Renoir)
1944
Double Indemnity (Billy Wilder)
Frenzy (Hets, Sweden, Alf Sjoberg)
Henry V (UK, Laurence Olivier)
Meet Me in St Louis (Vincente Minnelli)
1945
Brief Encounter (UK, David Lean)
Les Dames du Bois de Boulogne (France, Robert Bresson)
Detour (Edward G Ulmer)
Les Enfants du Paradis (France, Marcel Carne)
Mildred Pierce (Michael Curtiz)
Rome, Open City (Italy, Roberto Rossellini)
Victory in the Ukraine (Pobeda na Pravoberezhnoi Ukraine i izgnaniye nemetsikh zakhvatchikov za predeli Ukrainskikh sovietskikh zemel,USSR, Alexander Dovzhenko and Yuliya Solnseva)
1946
The Best Years of Our Lives (William Wyler)
The Big Sleep (Howard Hawks)
Five Women Around Utamaro (Utamaro O Meguro Gonin No Onna,
Japan, Kenji Mizoguchi)
It’s a Wonderful Life (Frank Capra)
The Killers (Robert Siodmak)
A Matter of Life and Death (UK, Michael Powell and Emeric Pressburger)
Notorious (Alfred Hitchcock)
Paisa (Italy, Roberto Rossellini)
1947
The Actress (Joyu, Japan, Teinosuke Kinugasa)
Black Narcissus (UK, Michael Powell and Emeric Pressburger)
Body and Soul (Robert Rossen)
Crossfire (Edward Dymtryk)
The Loves of Actress Sumako (Joyu Sumako No Koi, Japan, Kenji Mizoguchi)
Out of the Past (Jacques Tourneur)
Somewhere in Europe (Valahol Europaban, Hungary, Geza Radvanyi)
Stolen Frontier (Uloupená hranice, Czechoslovakia, Jiri Weiss)
Village Schoolteacher (Selskaya uchitelnitsa, USSR, Mark Konskoi)
Wozzek (East Germany, Georg C Klaren)
1948
Bicycle Thief (Ladri di biciclette Italy, Vittorio de Sica)
Bitter Rice (Riso Amaro, Italy, Giuseppe De Santis)
Drunken Angel (Yoidore Tenshi, Japan, Akira Kurosawa)
The Earth Trembles (Terra Trema, Italy, Luchino Visconti)
The Lady from Shanghai (Orson Welles)
Letter from an Unknown Woman (Max Ophuls)
Louisana Story (Robert J Flaherty)
Red River (Howard Hawks)
The Red Shoes (UK, Michael Powell and Emeric Pressburger)
She Wore a Yellow Ribbon (John Ford)
The Treasure of the Sierra Madre (John Huston)
1949
Beauty and the Beast (La Beaute du Diable, France-Italy, Rene Clair)
Gun Crazy (Joseph H Lewis)
Orpheus (France, Jean Cocteau)
Le Sang des Betes (France, Georges Franju)
She Wore a Yellow Ribbon (John Ford)
The Third Man (UK, Carol Reed)
1950
Les Enfants Terribles (France, Jean-Pierre Melville)
In a Lonely Place (Nicholas Ray)
Los Olvidados (Mexico, Luis Bunuel)
Rashomon (Japan, Akira Kurosawa)
La Ronde (France, Max Ophuls)
Sunset Boulevard (Billy Wilder)
