I see your 10 movies and raise you 20
the 1940's had a bunch of great films and I had a hard time cutting my list to 20
1 The Third Man (1949)
2 Citizen Kane (1941)
3 Notorious (1946)
4 The Treasure of the Sierra Madre (1948)
5 Casablanca (1942)
6 Rebecca (1940)
7 The Maltese Falcon (1941)
8 It's a Wonderful Life (1946)
9 The Great Dictator (1940)
10 The Wolf Man (1941)
11 The Big Sleep (1946)
12 The Grapes of Wrath (1940)
13 Ministry of Fear (1944)
14 Bitter Rice (1949)
15 49th Parallel (1941)
16 Kind Hearts and Coronets (1949)
17 The Philadelphia Story (1940)
18 Henry V (1944)
19 His Girl Friday (1940)
20 Cat People (1942)
honorable mentions:
Double Indemnity (1944)
The Best Years of Our Lives (1946)