Hmmm.... do I smell a term paper? ;-)

In any case, the fact that people who aren't even big fans of the films quote them because the (OT) dialogue has become part of our lexicon and so many characters are used as descriptive monikers for individuals (Old wise guy? Yoda. Mean guy? Vader. Hot shot? Han Solo.) is evidence enough of the cultural influence.

Most of the more recent documentaries (like the one from '97 hosted by Howie Long) show multiple examples of how the OT films have influenced our culture.

Just an example from personal experience, I know that AT&T employees call their round logo-thingy the "death star."