There is perhaps no extended universe with more depth, expanded mythology and plotlines than that of Star Wars (and yes, I am including the Star Trek books Shatner co-authored in order to bring Kirk back to life for some reason). So now that Disney has its mouse paws gripped firmly around the galaxy far, far away, it's not that strange a guess to assume that they may look into the countless novels, series and comic books to search out an appropriate plotline to serve for the proposed sequel trilogy which will begin with Episode 7 in 2015.
There are many considerations and directions Disney could take for this new installment. They could go the direct sequel route, with events taking place in the aftermath of the Battle of Endor and the destruction of the second Death Star. If that were the case it would require re-casting the roles of Luke, Leia and Han Solo. Is that entirely a bad thing? I could kind of care less about who plays the others, but come on, Harrison Fordis Han Solo. Would you ever want to see someone else playing that role?
But the most famous Star Wars EU storyline has come from Timothy Zahn's Thrawn Trilogy, beginning with 'Heir to the Empire.' While the main thrust of the story is bureaucratic in nature (Oh, hello worst part of the prequels), with the last of the Empire being thwarted and the beginnings of the New Republic starting to form, it also introduces Mara Jade as the future Mrs. Luke Skywalker and Grand Admiral Thrawn, one of the most well-received villains of the post-Jedi stories. It's also a little light on the Jedi training and force stuff, which might be a welcome meal after all the 'younglings' nonsense of the prequels. Again though, this would require recasting some of the most famous roles in film history and I'm not sure I'm ready for Gerard Butler to play Han just quite yet.
'The Hand of Thrawn' is another possibility. Attack of the Clones was one of the most flubbed love stories in movie history. The relationship of Anakin and Padme, I mean Queen Amidala, I mean Senator Amidala was so forced and ill conceived that it reminded me of when I used to take my sister's Ken and Barbie dolls and just smush their formless genitals up against one another. So if Disney wanted to try their hands at a Star Wars love story again, 'Hand of Thrawn' could be the story to use, letting romance blossom between (again, re-cast) Luke Skywalker and Mara Jade.
Then there's 'The Jedi Academy' series, detailing Luke Skywalker's early attempts at establishing a new Jedi Order. This series takes place almost a decade after Jedi which could mean that re-casting Luke Skywalker might be acceptable as he would've aged a bit from Episode 6 and as he would be seen in a different incarnation, it might not be so blasphemous. If the re-establishment and training of the Jedi is the story Disney wants to tell, then they can also adapt 'I, Jedi', which occurs during the same time period as the former, but casts a new student with his own story and personal agenda as the forefront of the plot and Luke Skywalker is featured, but more in the background.
More likely though, the inevitability will be that Disney chooses to go with adapting a form of 'The Legacy of the Force' series, with Han and Leia's children Jacen, Jaina and Anakin, as well as Luke and Mara-Jade's son Ben. This is clearly the Twilight version of Star Wars, with plenty of roles for sulking emo actors with Robert Pattinson's haircut and Kristen Stewart's sour puss. But there's also plenty of lightsaber battles, family betrayal and a climactic fight between brother and sister. It also takes place decades after Jedi which would mean that Harrison Ford, Mark Hamill and Carrie Fisher could potentially reprise their roles as they'd be age appropriate.
Or of course Disney could very well just start from scratch with a truly original story featuring characters we've never seen before or new stories featuring fan favorites. But with a 2015 release date penciled in, it probably won't be too long before the first tidbits of plot begin to fall.