Basically, we were mulling over to what extent Jackson's trilogy of HOBBIT films being made as prequels to his LORD OF THE RINGS films of a decade and more before can be considered analogous to Lucas's prequels to his original STAR WARS trilogy.
Having been tremendously impressed with STAR WARS when it first came out, and unimpressed by pretty much all the ones that followed, I was stunned to learn that people approaching the Lucas films for the first time nowadays start with PHANTOM MENACE. I can't imagine how this must skew the viewing experience for seeing the original movie as the fourth in a series. Such viewers know who Darth Vader is the first time he appears -- they've seen the mask and heard the breath at the end of SITH. They know who Leia is as soon as they learn her foster-father's name, and that she and Luke are brother and sister. It must be like people who read THE SILMARILLION before THE HOBBIT: I know there are some, and that the sequence works for them, but it's so different from my own experience that it's hard for me to properly envision it.
Of course, where the analogy between Lucas and Jackson breaks down is that Jackson is adapting pre-existing, well-known books. He varies from the books a good deal in detail (more than I wd like) but keeps to the main overall plot and structure. Plus, Tolkien's HOBBIT is not a 'prequel' to his LORD OF THE RINGS -- THE HOBBIT came first, and LotR was written as a sequel (though Jackson's film HOBBIT is a prequel to his earlier LotR films).
By contrast, Lucas's fourth, fifth, and sixth movies (1999-2005) are indeed prequels to the original STAR WARS (1977) and its two sequels (to be a prequel, a work must be made later but set earlier).
Except that while Jackson has everything that happens in THE HOBBIT already mapped out for him, and knows exactly how it shd sync up with the start of LotR, Lucas just makes up things as he goes along (despite claims to the contrary), creating all kinds of continuity problems for himself in the process. Seeing how careful Jackson is in AN UNEXPECTED JOURNEY to touch bases again and again with elements in his LotR films, and how hard he works not to clash in this film with what's already been established in the earlier ones, I suspect the final fit between the HOBBIT films and the LotR films will be as seamless as he can make it.
Also, Jackson's LotR is really just a single very long movie released in three yearly installments (similar to Tolkien's LotR, itself not a trilogy but a three-volume novel), a model THE HOBBIT seems sure to follow. Not so both Lucas's original STAR WARS films (1977-1983) and the follow-up prequels, which are true trilogies: a set of three linked but essentially stand-alone works. And with longer gaps, both between the trilogies and between the films within each trilogy.
So while I can see some surface similarity, I think the analogy doesn't hold. Lucas is Lucas, and Jackson is Jackson. Luckily for me, I prefer Jackson -- but I still remember the 'Beatlemania' moment when the original STAR WARS came out of nowhere and blew everybody away. If only he'd stopped while he was ahead . . . As I think Jackson will stop when he comes to the end of THE HOBBIT.
current reading: TOLKIEN'S BAG END (Morton), THE LAST YGGDRASIL (Young), SPEAKING FROM AMONG THE BONES (the latest Flavia de Luce novel)