What's fascinating about the original Star Wars film is how much of it is borrowed while still maintaining a feeling of pure inventiveness. This was a time when George Lucas solidly understood both the power of film and the power of mythology, and the result is one of the most beloved films of all time.
Admittedly, there are elements of the film that are pure camp, but they fit within the world Lucas has created, and only add to the experience. The film gave us iconic characters like the terrifying Darth Vader, the rogueish Han Solo, and the wise Obi Wan Kenobi. It is a classic tale of good vs. evil, and the power of small groups of people to make big change.
Even watching Star Wars today, it is easy to see how this film succeeded 30 years ago both in enrapturing audiences of the time, and in changing the face of filmmaking forever.