Network
Written by Paddy Chayefsky
Directed by Sydney Lumet
Starring Faye Dunaway, William Holden, Peter Finch, Robert Duvall, and Ned Beatty
1976
Peter Finch won the 1976 Best Actor Oscar for this 'speech':
(Thanks to Dori Monson of KIRO 710 & FM 97.3)