The Library of Congress has announced the films selected for preservation. The link has the full press release and descriptions of the films you may not recognize. I've bolded the theatrical releases I'd recommend - some of which are obvious but still.
Link....
Films Selected to the 2011 National Film Registry
Allures (1961)
Bambi (1942)
The Big Heat (1953)
A Computer Animated Hand (1972)
Crisis: Behind A Presidential Commitment (1963)
The Cry of the Children (1912)
A Cure for Pokeritis (1912)
El Mariachi (1992)
Faces (1968)
Fake Fruit Factory (1986)
Forrest Gump (1994)
Growing Up Female (1971)
Hester Street (1975)
I, an Actress (1977)
The Iron Horse (1924)
The Kid (1921)
The Lost Weekend (1945)
The Negro Soldier (1944)
Nicholas Brothers Family Home Movies (1930s-40s)
Norma Rae (1979)
Porgy and Bess (1959)
The Silence of the Lambs (1991)
Stand and Deliver (1988)
Twentieth Century (1934)
War of the Worlds (1953)
Link....
Films Selected to the 2011 National Film Registry
Allures (1961)
Bambi (1942)
The Big Heat (1953)
A Computer Animated Hand (1972)
Crisis: Behind A Presidential Commitment (1963)
The Cry of the Children (1912)
A Cure for Pokeritis (1912)
El Mariachi (1992)
Faces (1968)
Fake Fruit Factory (1986)
Forrest Gump (1994)
Growing Up Female (1971)
Hester Street (1975)
I, an Actress (1977)
The Iron Horse (1924)
The Kid (1921)
The Lost Weekend (1945)
The Negro Soldier (1944)
Nicholas Brothers Family Home Movies (1930s-40s)
Norma Rae (1979)
Porgy and Bess (1959)
The Silence of the Lambs (1991)
Stand and Deliver (1988)
Twentieth Century (1934)
War of the Worlds (1953)