This is a harder than usual list to make, because there's so many ways to measure a director's career. I decided to only include directors from whom I've seen three films, thinking that that was the minimum necessary to get a handle on a director's style and quality. Unfortunately, I've only seen two films from: Ida Lupino, Chantal Ackerman, Agnes Varda, Jane Campion and Kathryn Bigelow, all of whom have something in common with each other but not with anyone else on my list.
I've included the years when the directors were active (with some arbitrariness around a lot of the start dates, given shorts and TV and student films) because i think it's interesting to compare career lengths (did you know Martin Scorsese has had a career almost as long as Hitchcock and Kurosawa?). Also included are my three favorite films from each director.
1. Alfred Hitchcock (1925-1976)
Vertigo, Rear Window, North By Northwest
2. Howard Hawks (1926-1970)
Bringing Up Baby, Rio Bravo, The Big Sleep
3. Michael Powell (1931-1978)
The Red Shoes, Black Narcissus, A Canterbury Tale
4. Yasujiro Ozu (1927-1962)
Late Spring, Tokyo Story, Early Summer
5. John Ford (1917-1966)
The Searchers, Stagecoach, The Quiet Man
6. Orson Welles (1941-1978)
Touch of Evil, Chimes at Midnight, Citizen Kane
7. FW Murnau (1919-1931)
Sunrise, Tabu, Nosferatu
8. Akira Kurosawa (1943-1993)
Seven Samurai, Ran, Rashomon
9. Wong Kar-wai (1988-present)
Chungking Express, 2046, Fallen Angels
10. Terrence Malick (1973-present)
Days of Heaven, The New World, The Thin Red Line
11. Eric Rohmer (1962-2007)
The Green Ray, My Night at Maud's, Pauline at the Beach
12. Roberto Rossellini (1942-1977)
Voyage to Italy, Rome, Open City, The Age of the Medici
13. Josef von Sternberg (1925-1957)
The Docks of New York, Morocco, Shanghai Express
14. Charles Chaplin (1914-1967)
City Lights, The Gold Rush, Modern Times
15. Jean-Luc Godard (1960-present)
Pierrot le fou, A Woman is a Woman, Contempt
16. Jacques Tati (1949-1974)
Playtime, M. Hulot's Holiday, Mon Oncle
17. Jean Renoir (1925-1970)
The Rules of the Game, The River, The Grand Illusion
18. Buster Keaton (1920-1965)
The General, Sherlock Jr, Steamboat Bill Jr
19. Hou Hsiao-hsien (1980-present)
Millenium Mambo, Three Times, The Puppetmaster
20. Nicholas Ray (1949-1980)
Johnny Guitar, In a Lonely Place, Bitter Victory
21. Vincente Minnelli (1943-1976)
The Band Wagon, An American in Paris, The Pirate
22. Wes Anderson (1996-present)
Rushmore, The Royal Tenenbaums, The Life Aquatic
23. Samuel Fuller (1949-1989)
The Steel Helmet, The Big Red One, Park Row
24. Ernst Lubitsch (1914-1948)
The Shop Around the Corner, Trouble in Paradise, Ninotchka
25. Alain Resnais (1948-present)
Last Year at Marienbad, Hiroshima mon amour, Wild Grass
26. Jim Jarmusch (1980-present)
Dead Man, Stranger than Paradise, Ghost Dog
27. Anthony Mann (1939-1968)
Winchester '73, The Black Book, The Naked Spur
28. Frank Borzage (1913-1959)
No Greater Glory, Moonrise, Seventh Heaven
29. Martin Scorsese (1967-present)
Taxi Driver, Mean Streets, The Last Temptation of Christ
30. Carl Theodor Dreyer (1919-1964)
Day of Wrath, Vampyr, Ordet
31. Joel & Ethan Coen (1984-present)
The Big Lebowski, Miller's Crossing, Barton Fink
32. Fritz Lang (1919-1960)
The Big Heat, M, Scarlet Street
33. Krzysztof Kieslowski (1966-1994)
Three Colors, The Double Life of Veronique, The Decalogue
34. Stanley Kubrick (1955-1999)
2001, Eyes Wide Shut, The Shining
35. Michelangelo Antonioni (1950-2004)
L'Eclisse, Blow Up, L'Avventura
36. Quentin Tarantino (1992-present)
Pulp Fiction, Kill Bill, Inglourious Basterds
37. Jacques Demy (1961-1988)
The Umbrellas of Cherbourg, Lola, The Young Girls of Rochefort
38. Woody Allen (1966-present)
Annie Hall, Manhattan, The Purple Rose of Cairo
39. John Woo (1974-present)
Hard-Boiled, The Killer, Last Hurrah for Chivalry
40. Douglas Sirk (1935-1959)
Written on the Wind, There's Always Tomorrow, All That Heaven Allows
41. Luis Buńuel (1929-1977)
The Exterminating Angel, Un chien andalou, Simon of the Desert
42. Otto Preminger (1931-1979)
Anatomy of a Murder, Laura, Advise & Consent
43. Johnnie To (1980-present)
PTU, Exiled, The Mission
44. Leo McCarey (1921-1962)
The Awful Truth, Make Way for Tomorrow, The Bells of St. Mary's
45. Raoul Walsh (1913-1964)
The Strawberry Blonde, Regeneration, High Sierra
46. Robert Bresson (1943-1983)
Au hasard Balthazar, Pickpocket, Diary of a Country Priest
47. DW Griffith (1908-1931)
Intolerance, The Musketeers of Pig Alley, True Heart Susie
48. King Vidor (1913-1959)
Street Scene, Our Daily Bread, The Big Parade
49. Michael Curtiz (1912-1961)
Casablanca, The Adventures of Robin Hood, The Sea Hawk
50. George Cukor (1930-1981)
The Philadelphia Story, A Star is Born, It Should Happen To You
51. Satyajit Ray (1955-1991)
The Music Room, Charulata, Mahanagar
52. Apichatpong Weerasethakul (2000-present)
Tropical Malady, Blissfully Yours, Uncle Boonmee Who Can recall His Past Lives
53. Kenji Mizoguchi (1923-1956)
Ugetsu, Sansho the Bailiff, Story of the Late Chrysanthemums
54. Sergei Eisenstein (1923-1948)
Alexander Nevsky, Ivan the Terrible, Battleship Potemkin
55. Jacques Tourneur (1931-1966)
Out of the Past, Cat People, Stars in My Crown
56. William Wyler (1925-1970)
The Letter, Dodsworth, The Best Years of Our Lives
57. Preston Sturges (1940-1955)
The Lady Eve, Unfaithfully Yours, Sullivan's Travels
58. Frank Capra (1922-1961)
Mr. Smith Goes to Washington, It's a Wonderful Life, It Happened One Night
59. Hiroshi Shimizu (1924-1959)
Japanese Girls at the Harbor, Mr. Thank You, Ornamental Hairpin
60. Sergio Leone (1961-1984)
Once Upon a Time in the West, The Good The Bad & The Ugly, For a Few Dollars More
61. Hayao Miyazaki (1979-present)
Spirited Away, Howl's Moving Castle, Ponyo on the Cliff by the Sea
62. Hong Sangsoo (1996-present)
Oki's Movie, Hahaha, Like You Know it All
63. Max Ophuls (1931-1955)
Madame de. . ., Letter from an Unknown Woman, Lola Montes
64. Richard Linklater (1988-present)
Dazed and Confused, Slacker, Before Sunrise
65. Steven Spielberg (1971-present)
Jaws, Raiders of the Lost Ark, Empire of the Sun
66. Jia Zhangke (1995-present)
The World, Platform, Still Life
67. David Fincher (1992-present)
Fight Club, The Social Network, Se7en
68. Billy Wilder (1942-1981)
Double Indemnity, Sunset Blvd., Some Like it Hot
69. Tsai Ming-liang (1991-present)
What Time is it There?, Goodbye Dragon Inn, I Don't Want to Sleep Alone
70. Joseph L. Mankiewicz (1946-1972)
All About Eve, The Ghost & Mrs. Muir, The Barefoot Contessa
71. Abbas Kiarostami (1973-present)
Certified Copy, Taste of Cherry, The Wind Will Carry Us
72. Werner Herzog (1968-present)
Fitzcarraldo, Aguirre the Wrath of God, Bad Lieutenant: Port of Call New Orleans
73. Victor Sjostrom (1912-1937)
The Wind, He Who Gets Slapped, The Phantom Carriage
74. Michael Mann (1981-present)
Miami Vice, Last of the Mohicans, Heat
75. Jean-Pierre Melville (1949-1972)
Le Samourai, Army of Shadows, Bob le flambeur
76. Olivier Assayas (1986-present)
Irma Vep, Carlos, Summer Hours
77. Bob Fosse (1969-1983)
All that Jazz, Cabaret, Lenny
78. Peter Watkins (1956-present)
La Commune (Paris 1971), Culloden, The War Game
79. Stanley Donen (1949-1984)
Singin' in the Rain, Charade, Give a Girl a Break
80. Guy Maddin (1986-present)
Archangel, My Winnipeg, Heart of the World
81. David Lean (1942-1984)
Lawrence of Arabia, Brief Encounter, Doctor Zhivago
82. Clint Eastwood (1971-present)
Unforgiven, The Outlaw Josey Wales, Flags of Our Fathers
83. James Whale (1930-1941)
Frankenstein, Show Boat, The Invisible Man
84. Andrei Tarkovsky (1962-1986)
Andrei Rublev, Stalker, Solaris
85. Whit Stillman (1990-present)
Metropolitan, The Last Days of Disco, Barcelona
86. Lau Kar-leung (1973-present)
The 36th Chamber of Shaolin, 8 Diagram Pole Fighter, Drunken Master II
87. David Lynch (1977-present)
Mulholland Dr., Lost Highway, Inland Empire
88. Paul Thomas Anderson (1996-present)
There Will Be Blood, Punch-Drunk Love, Boogie Nights
89. Francis Ford Coppola (1963-present)
Apocalypse Now, The Godfather Part II, Bram Stoker's Dracula
90. George Stevens (1930-1970)
Swing Time, Gunga Din, Giant
91. Robert Altman (1957-2006)
The Long Goodbye, McCabe & Mrs. Miller, Popeye
92. Federico Fellini (1950-1990)
8 1/2, Nights of Cabiria, La dolce vita
93. Zhang Yimou (1987-present)
House of Flying Daggers, Hero, The Road Home
94. Joe Dante (1976-present)
Matinee, Gremlins, The Burbs
95. Danny Boyle (1994-present)
Trainspotting, 127 Hours, A Life Less Ordinary
96. Abel Ferrara (1979-present)
New Rose Hotel, The Addiction, Bad Lieutenant
97. Cecil B. DeMille (1914-1956)
The Sign of the Cross, The Ten Commandments, The Cheat
98. Ang Lee (1992-present)
Crouching Tiger Hidden Dragon, Sense and Sensibility, Eat Drink Man Woman
99. Sam Peckinpah (1962-1983)
The Wild Bunch, Ride the High Country, Pat Garret & Billy the Kid
100. William Friedkin (1967-present)
The French Connection, To Live and Die in LA, Blue Chips