What better film to serve as an example of the importance of location. NYC is indeed a 3rd character in this story. Travis and the city of New York are connected at the hip, and the city in all its loneliness and filth, help explore the inner mind of the character.
Another great example. It's either the barren, desert landscape which help defines the characters, or the honky tonk bars and diners. The small cabin, the old cars - every location in this film is perfect.
RAISE THE RED LANTERN
Amazing location. It feels like you can touch it. The director here really puts us there - he creates a world which we are aloud to enter and live in - which helps to explore and understand the characters and story.