I can't explain why I didn't post this when this thread started, but...

"Key Largo" (1948). Johnny Rocco (Edward G. Robinson) and his mob are holed up in a Florida Keys hotel, holding hostage the owner (Lionel Barrymore), his daughter (Lauren Bacall) and a visitor (Humphrey Bogart) during a hurricane. Claire Trevor, as Rocco's moll, won Best Supporting Actress Oscar, but Robinson, as usual, supplies the juice. Robinson in "Little Caesar" was a choir boy compared with his Johnny Rocco in "Key Largo," possibly the nastiest gangster ever. Robinson, IMO, the most underrated great actor in Hollywood history.