Let me just post a long list. All based on what I've seen, of course— hence some major omissions, but whatever. Special recommendations in bold.
CUBA
Soy Cuba (Mikhail Kalazatov)
Memories of Underdevelopment (Tomas Gutierrez Alea)
EASTERN EUROPE
Ashes and Diamonds (Andrzej Wajda)
Daisies (Vera Chytilova)
WR: Mysteries of the Organism (Dušan Makavejev)
Satantango, Werckmeister Harmonies (Béla Tarr)
FRANCE
A Propos de Nice, L'Atalante (Jean Vigo)
The Rules of the Game (Jean Renoir)
Pickpocket, Au Hasard Balthazar, Mouchette (Robert Bresson)
The 400 Blows (François Truffaut)
Breathless, Masculin-Feminin, 2 or 3 Things I Know About Her, Vivre Sa Vie (Jean-Luc Godard)
La Jetée, Sans Soleil (Chris Marker)
Beau Travail, White Material (Claire Denis)
GERMANY
Faust (F. W. Murnau)
The Blue Angel (Josef von Sternberg)
Pandora's Box (G. W. Pabst)
Metropolis, M (Fritz Lang)
Aguirre: the Wrath of God, The Enigma of Kaspar Hauser, Lessons of Darkness (Werner Herzog)
Veronika Voss, Ali: Fear Eats the Soul, Berlin Alexanderplatz, World on a Wire (Rainer Werner Fassbinder)
JAPAN
I Was Born, But..., Late Spring, Tokyo Story, Late Spring, Good Morning (Yasujirō Ozu)
The Story of the Late Chrysanthemums, Sansho the Bailiff, Ugetsu (Kenji Mizoguchi)
The Seven Samurai, Stray Dog, Rashomon, Ran (Akira Kurosawa)
Woman in the Dunes (Hiroshi Teshigahara)
Akira (Katsuhiro Otono)
My Neighbor Totoro (Hayao Miyazaki)
RUSSIA/USSR
Battleship Potemkin (Sergei Eisenstein)
Earth (Alexander Dovzhenko)
Shadows of Our Forgotten Ancestors (Sergei Parajanov)
Andrei Rublev, The Mirror, Solaris (Andrei Tarkovsky)
Russian Ark (Alexander Sokurov)
SCANDINAVIA
The Passion of Joan of Arc (Carl Theodor Dreyer)
The Seventh Seal, Fanny and Alexander (Ingmar Bergman)
The Celebration (Thomas Vinterberg)
TAIWAN
City of Sadness, The Puppetmaster (Hou Hsiao-Hsien)
A Brighter Summer Day, Yi Yi (Edward Yang)
Goodbye Dragon Inn (Tsai Ming-Liang)
MISC.
Pather Panchali, Jalsaghar (Satyajit Ray) — India
The Spirit of the Beehive (Victor Erice) — Spain
Brightness (Souleymane Cissé) — Mali
Tropical Malady, Uncle Boonmee Who Can Recall His Past Lives (Apichatpong Weerasethakul) — Thailand