AFI's 100 Greatest American Movies of All Time
The very first edition of AFI's 100 Years...100 Movies is a list of the 100 greatest American films of all time.
In 1998, AFI invited more than 1,500 leaders from across the American film community – screenwriters, directors, actors, producers, cinematographers, editors, executives, film historians and critics among them – to choose from a list of 400 nominated films compiled by AFI and select the 100 greatest American movies.
Source: http://www.afi.com/100years/movies.aspx