I recently watched all three original Star Wars films for the first time since seeing them in theaters in 1997 (I bought the DVD set in the fall of 2004). But before watching episodes IV and V, I read the novelizations, as I also did immediately after episode VI. In any such converstion of media, the source material is almost always superior, and this was no exception: the books were vastly dependent on the on-screen action to detail what was happening. The most enjoyable novelization of the three was Return of the Jedi, which offered some useful insight into the characters' thoughts: Han Solo's evolution toward selflessness; Luke's struggle with the Dark Side; Vader's machinations against both his son and emperor. I had hoped for a bit more detail into Vader's final redemptive act, but none was forthcoming.
The only other movie novelization I've ever read was Attack of the Clones, which had numerous exclusive scenes (both deleted from the movie and created by the book's author). I guess I was hoping for a similar treatment from the original trilogy.
In related news, IGN.com recently posted its "Top 25 Movie Franchises of All Time". George Lucas had the winning entry, of course.
You are right about most written conversions of a movie; the book is not much better than a re-statement of the movie script, with descriptions of the set in the appropriate places. The one exception would be if the original screenplay author is utilitzed in creating the book, when parts that were cut from the movie may make their way into the book. I often wonder how Tolkien would have felt with the latest movie adaptation of his trilogy, understanding the constraints of a theatrical production.
Regarding the Star Wars franchise: I had heard years ago that Lucas had envisioned not only the three parts that made up the original Star Wars movies, but also a part of the story that preceeded them (that was why the original Star Wars was renamed "Episode IV" – don't remember if it said that in the original release of the movie or not), and a part of the story that took place AFTER episodes IV-VI. Has anyone heard whether or not he still has plans for episodes VII to IX?
And just to keep things interesting, if you enjoy parodies, be sure to see the short online series, "Chad Vader, Day Shift Manager" at http://splu.net/chadvader.htm. Funny stuff, and very well done Vader voice.
Lucas has said there will be no more Star Wars movies. There's not much more info than that beyond conjecture.
There are plenty of books that detail the events before, during, and after the first three films; of course, these are non-canonical.
George Lucas reported that the investment and gamble of movies is too expensive to warrant further pursuit. His next live-action Star Wars project is a TV series, as detailed at Wikipedia.
I'd also heard about the theoretical 9-episode story arc supposedly conceived by George Lucas. (Although I've never been clear whether the grand plan was envisioned before or after the success of the first movie!)
After Episode III when Lucas said "No more!", I Googled around to see if I could find anything about what "might have been". There are several sites and references that discuss the last three episodes, including one that purports to involve an interview with George Lucas. Unfortunately, if I was a betting man, I'd have to bet that the sites and claims are all fanciful. :(
A more charitable version is that any original vision Lucas had has been overtaken in the (many!) intervening years by the books and the aging of the original actors.
Posted just today on TheForce.net is a revival of the rumor about Episodes VII – IX. It doesn't come from a verifiable source, though.
Here's a recent video interview in which Lucas again says "The Skywalkers are done" and that there will be no more Star Wars films.