Chewtobacca said:
I thought of the Maltese Falcon too. I agree that the Falcon itself is a MacGuffin because it is simply there to motivate and evoke certain responses from the characters: it could, if the story were renamed, be replaced by anything else without detriment to the plot.
Exactly! "The Maltese Falcon" could be replaced with valuable microfilm, the case in "Pulp Fiction" could be the Maltese Falcon, and "North by Northwest" could be about finding a diamond.