The elitist class of cinema-goers would probably say the 70s. You had The Godfather I and II, Apocalypse Now, Alien, One Flew Over The Cuckoo's Nest, The Deer Hunter, Taxi Driver, The Exorcist, Chinatown, Star Wars: A New Hope, and Jaws. Plenty more after that too. 

I [i]might[/i] agree with that, but my heart is with the 80s and 90s. Goonies, Karate Kid, The Lost Boys, Scream, Die Hard, Jurassic Park, Grosse Point Blank, The Matrix. Yeah, 80s and 90s are a wild and good time for film.