Top 10 movies of 1973:

Werner Herzog's Aguirre, the Wrath of God
William Friedkin's The Exorcist
George Roy Hill's The Sting
Martin Scorcese's Mean Streets
Terrence Malik's Badlands
George Lucas' American Graffiti
Fred Zinneman's The Day of the Jackal
Robert Clouse's Enter the Dragon
Franklin Schaffner's Papillon
Sidney Lumet's Serpico

Runner up:

James Bridges' The Paper Chase