Starting with Blade Runner, then Raiders, Empire Strikes Back, E.T.,Temple of doom,Return of the Jedi,and then the Last Crusade...Also any other film staring Harrison Ford...
I dont think we can possibly say if the 80's was a great decade for cinema, well for starters i suppose it was a great decade for SS and GL but the mist of nostalgia has yet to clear from that period.
I would say that the 70's were a far worse era for "great" movies than the 80's.
Indiana Jones
2 Star Wars (ESB & RotJ)
Back to the Future
Blade Runner
Just to name a few, I would say that the 90's brought about some great movies too, but the crown really belongs to the 1930's-1950's era films.
A Clockwork Orange (1971)
The French Connection (1971)
The Last Picture Show (1971)
McCabe and Mrs. Miller (1971)
Cabaret (1972)
The Godfather (1972)
American Graffiti (1973)
The Exorcist (1973)
Mean Streets (1973)
Blazing Saddles (1974)
Chinatown (1974)
The Conversation (1974)
The Godfather Part II (1974)
Jaws (1975)
Nashville (1975)
One Flew Over The Cuckoo's Nest (1975)
Network (1976)
Taxi Driver (1976)
Annie Hall (1977)
Close Encounters of the Third Kind (1977)
Star Wars (1977)
The Deer Hunter (1978)
Alien (1979)
Apocalypse Now (1979)
Manhattan (1979)
I said that the 70's were a bit worse off than the 80's for movies...not terrible. I like several films that came from the 70's, but I think the point has been made.