"Luke I am your Father" will be preserved for years to come.  The Library of Congress chose The Empire Strikes Back as one of their annual films for preservation.  Each year the group selects twenty-five films to archive for all time.  They're not selected based on number of tickets sold, but on their historical significance to American Culture.

Spanning the period 1891-1996, the films named to the registry range from a rare glimpse of San Francisco before the 1906 earthquake and the political thriller "All the President’s Men" to George Lucas’ student film in 1967 and his sci-fi special-effects extravaganza "The Empire Strikes Back." Also included in the registry are lesser-known, but culturally vital films such as the black independent film "Cry of Jazz," Luis Valdez’s "I Am Joaquin" and John Huston’s war documentary "Let There Be Light," which was banned by the War Department for 35 years. This year’s selections bring the number of films in the registry to 550.

Among the other films included are Airplane!, All The President's Men, Malcolm X and The Pink Panther.  Get the complete list here

2010 National Film Registry Announced - The Library Today (Library of Congress).