The Immigrant (1917) with Edna Purviance and Henry Bergman. Chaplin himself was very pleased with this film - he thought it was one of his best shorts.
Chaplin always changed his thoughts about his films, but he said the followings:
The film he wanted to be remembered by was The Gold Rush (1925).
The film he thought was the most clever he had ever made was Monsieur Verdoux (1947).
As late as 1974 -
"The Immigrant" touched me more than any other film I made".
Charles Chaplin, My Life In PIctures”“.