ray_afraid said:

^Certainly more people call it "Star Wars" than "A New Hope".

True, but Star Wars could refer to the film, the trilogy, the (gack!) saga, or the franchise. There are cases where you need some way to specify one meaning because you can't get it entirely from context--I've certainly had to do it once or twice.

And you can either say "Star Wars--er, the first film... er, no, not episode one, episode four... er, except it doesn't have an episode number... uh, what was I saying again?", or you can say A New Hope.

The terminology may not be accurate, but if it communicates the needed information correctly, and it doesn't require the listener to have any especially deep knowledge of the subject just to unpack the terms, the term has done its job. I friggen' hate calling it A New Hope personally, but I can see its utility in certain contexts.

EDIT: davextreme said it first :(