Where does one begin? I'm sure to leave out a dozen or more, but I consider these to be among my favorite classic movies (classic for this purpose meaning released before 1960):
In no particular order:
The Apartment
It Happened One Night
Casablanca
Destry Rides Again
Stagecoach
Angel and the Bad Man
Red River
The Searchers
Double Indemnity
The Lady Eve
Our Man Godfrey
The Adventures of Robin Hood
Captain Blood
They Died With their Boots On
Sabrina
Roman Holiday
A Nun's Story
Love in the Afternoon
The Maltese Falcon
The Postman Always Rings Twice
Bringing Up Baby
Alice Adams
Mr. Smith Goes to Washington
Mr. Deeds Goes to Town
Treasure of the Sierra Madre
The Thin Man
Another Thin Man
Here Comes Mr. Jordan
Sunset Boulevard
The Big Sleep
White Heat
A Walk in the Sun
Rear Window
Rebecca
The Lady vanishes
The 39 Steps
Saboteur
Notorious
I'm just gonna cut it "short" there. There are so many titles I can't remember, so many I've simply overlooked. And that's with a 1960 cut-off!
I watch too many movies lol. And I've watched the overwhelming majority of the movies listed multiple times!
North by Northwest!
Stop!!
Annie Oakley