Someone mentioned this on the John Hughes thread, and I was kind of surprised about it myself, but he only ever directed eight movies, all of them between 1984 and 1991, though did serve as a writer and/or producer on many other films.
Judd Apatow is another whose body of work seems like it should be larger. “Funny People” is only his third movie as director, even though it seems like he’s had his name plastered on almost every raunchy comedy that’s come out the past few years.
Quentin Tarantino is notorious in this regard. He’s only ever directed six movies (five if you want to count the Kill Bills as a single entity), but he’s had his name attached, in one form or another, to a number projects, either through cameo appearances, writing contributions or films where he simply “presents,” like “Hostel.”
Terrrence Malick. Most people in Hollywood agree he’s a genius (and Badlands and Days of Heaven clearly cements this view), but he’d only directed five films so far (there was a 20-year gap between Days of Heaven and The Thin Red Line).
The famous but overrated George Lucas:
Director:
THX1138 (1971)- Was this even a theatrical release?
American Grafitti (1973)
Star Wars (1977)
Then from working so much he took a 20-year hiatus before giving us the Star Wars prequel trilogy.
Preston Sturges wrote and directed some of the most original comedies Hollywood ever produced. Most of them were huge commerical failures, which is why he only got to do about 12 movies.
Actually, this isn’t true at all. At his peak (8 films from 1940-1044), he was raking in one of the biggest salaries in Hollywood–virtually unprecedented for a director in the industry. 3 Oscar nods and 1 win, he was at the top of his game and his movies did make Paramount a ton of money.
Things abruptly ended once The Great Moment was released (his first bomb), and the magic disappeared after that–he had a hard time writing movies subsequently, and a harder time getting support from studios. But to characterize his entire career as a long series of commercial failures is as wrong as you can be.
Judd Apatow, for all the press he gets, just directed his third movie, Funny People. Before that was Knocked Up and 40 YO Virgin, plus some F&G and Undeclared.
Stanley Kubrick. Directed a grand total of 16 movies in 48 years. Of those, 7 were during the 1950s. After that point (from Spartacus to Eyes Wide Shut), he directed 9 movies in 39 years.
To be at least a little fair: he didn’t direct during that time, but he wrote and produced a number of projects, including Indiana Jones. And, I think it’s become clear that his creative strengths don’t really lie in directing actors.
OTOH, he did also produce Howard the Duck during that time. 
Yes, it was released to cinemas. It even got the “Special Edition” treatment recently, which IMHO actually worked.
High on the list of accomplished directors with a small filmography is the Scottish directorAlexander Mackendrick. He is most remembered for classic Ealing comedies like Whisky Galore, The Man in the White Suit and The Ladykillers and also a great American film: Sweet Smell of Success which sadly was a commercial failure which badly hurt his career.
Kubrick’s work volume fit with his “methodical artist” approach to filmmaking. Kubrick’s legacy partly comes from the fact that every movie he made with creative control is a unique masterpiece.
Two that surprised me are Francis Ford Coppola and Martin Scorsese. They both have been working for decades and are highly regarded. But if you leave out the “quickies” they did when they were starting out and stuff like TV shows, shorts, documentaries, and concert films, they’ve each directed only nineteen feature films.
Finian’s Rainbow (1968)
The Rain People (1969)
The Godfather (1972)
The Conversation (1974)
The Godfather: Part II (1974)
Apocalypse Now (1979)
One from the Heart (1982)
The Outsiders (1983)
Rumble Fish (1983)
The Cotton Club (1984)
Peggy Sue Got Married (1986)
Gardens of Stone (1987)
Tucker: The Man and His Dream (1988)
The Godfather: Part III (1990)
Dracula (1992)
Jack (1996)
The Rainmaker (1997)
Youth Without Youth (2007)
Tetro (2009)
Boxcar Bertha (1972)
Mean Streets (1973)
Alice Doesn’t Live Here Anymore (1974)
Taxi Driver (1976)
New York, New York (1977)
Raging Bull (1980)
The King of Comedy (1982)
After Hours (1985)
The Color of Money (1986)
The Last Temptation of Christ (1988)
Goodfellas (1990)
Cape Fear (1991)
The Age of Innocence (1993)
Casino (1995)
Kundun (1997)
Bringing Out the Dead (1999)
Gangs of New York (2002)
The Aviator (2004)
The Departed (2006)
Nineteen features is not a miniscule career but both men somehow seem to have made more films than they actually did.
Terry Gilliam’s only made 11 feature-length films since 1975, with 2 more in the works.
David Lynch has only made 10 feature-length films since 1966. 11 if you count the Twin Peaks pilot, which was theatrical in Europe.
Of course, who’s famous to me might not be famous to others, but…
Bill Forsyth has only made 9 movies since 1980:
- Gregory’s Two Girls (1999)
- Being Human (1993)
- Breaking In (1989)
- Housekeeping (1987)
- Comfort and Joy (1984)
- Local Hero (1983)
- Gregory’s Girl (1981)
- Andrina (1981)
- That Sinking Feeling (1980)
Walter Murch is famous as an editor and sound guy, but he only directed one movie, Return To Oz. It’s a brilliant, wonderful, amazing movie, but asshole critics smugly destroyed it, and he never made another one. And that’s our loss.
Ray Lawrence has only made 3 movies, all fantastic:
- Jindabyne (2006)
- Lantana (2001)
- Bliss (1985) (one of my All-Time Favorite films)
From 1942 to 1984, David Lean is credited with directing 16 movies (17 if you count the TV documentary, Lost and Found: The Story of Cook’s Anchor). In fact, he only directed four feature films after 1957’s Bridge on the River Kwai.
Roman Polanski has made only 10 films since Chinatown 35 years ago, and only 16 since exploding onto the scene with Repulsion in 1965, almost 45 years ago!.
Baz Luhrmann has only directed four films since he debut in 1992 - Strictly Ballroom, Romeo + Juliet, Moulin Rouge, and Australia.
I wish he would up his production schedule a wee bit.
I can’t believe I forgot Baz! He’s too into the theater, dammit. I want movies. They last.
James Cameron has only directed five movies since striking gold with *The Terminator *in 1984. He has a sixth (Avatar) coming out later this year. His last feature film was Titanic, twelve years ago, though he has made two documentaries about undersea exploration since then.
Avatar (2009)
Titanic (1997)
True Lies (1994)
Terminator 2: Judgment Day (1991)
The Abyss (1989)
Aliens (1986)
The Terminator (1984)
Piranha Part Two: The Spawning (1981)
Xenogenesis (1978)
From what I hear, he’s pretty involved in the movies he produces. Just last year he produced four films.