1,The Maltese Falcon 2.Key Largo

1. The Caine Mutiney.

Very difficult to restrict it to three!

1. Casablanca

2. Key Largo

3. The Treasure of the Sierra Madre

I know this is a super old post, but here's mine:

1. The Maltese Falcon
2. African Queen
3. Casablanca (As a fourth it would without a doubt be Key Largo, but I didn't pick that as one of my top three because there are reasons other than Bogart that I like that movie)

This is a tough call to make. Listed chronologically, I'll go with Key Largo (1948), In a Lonely Place (1950), and The African Queen (1951). (I feel like also 1946's The Big Sleep should be included.)