That reminds me of the book "Plot" which used Star Wars (Empire Strikes Back in particular) as a typical example of a hero's journey. Except for a few variations, I did agree with it. I think Lucas was a genius in combining science fiction, mythologies, Japanese and Westerns, fairy tales (knights, princesses, epic adventures...) etc. using hero's journey and its archetypes almost to a T -- the result was a crowd-pleaser, to say the least. There's a DVD called "Joseph Campbell -- the Hero's Journey."
While I didn't adhere to the hero's journey precisely, I did use it to some good extent in shaping my novel, The Pacific Between. It's funny because a reader told me that he thought there was a nice parallel between the Wizard of Oz and my book, even though the stories were completely different. I credited that to the hero's journey: The Wizard of Oz is another great example of that.
In many ways, the hero's journey is usually both a physical and psychological one. One can argue that the Lord of the Rings is another good example of the hero's journey. But Campbell didn't invent it -- he simply observed and studied it, and laid it all out. The hero's journey dated back to Odyssey... and the most famous of all hero's journeys is the story of the Christ, which of course spawns off many other different types of stories (the Matrix?).
I for one thinks it's fascinating that how so many stories can somehow be categorized, with variations, as a hero's journey and how successful they are (Wizard of Oz, Cinderella, the Lord of the Rings, etc.) Obviously, not all stories are hero's journeys, but you know one when you see it.