I am slightly embarrassed to admit that over the New Years holiday, I flipped through a copy of Jedi vs. Sith: The Essential Guide to the Force. Yes, I just admitted that. No, I’m not sure why I did it.
In any case, I now know a few new things:
- There is an endless supply of almost meaningless detail about timelines, people, and battles that are sometimes self-contradictory and totally separate from the movies.
- There is a very cool Wikia site called “Wookiepedia” that has an almost endless supply of Star Wars information, and it’s free.
- There is a new comic book series called “Star Wars Legacy” that takes place 137 years after the Death Star was blown up, in a bleak future where the Republic & Jedi have fallen to a new order of the Sith.
As an interesting trivia item based on (3), I also discovered what I imagine it would look like if Darth Maul and Angelina Jolie had a baby: her name is Darth Talon. Enjoy.
Psychohistory 
I read most of the “extended galaxy” books for longer than I’d like to admit before the sheer volume (and decreasing quality) got to me.
But the one I would highly recommend is Dark Empire. It’s a graphic novel covering the aftermath of Return of the Jedi, as the galaxy plunges into civil war, various Imperial factions fight over the scraps of Palpatine’s empire, and Luke is tempted to the dark side as a last resort to… well, that part’s more fun if you read the book.
Legacy sounds interesting. I’m sure it will be an MMORPG before long.