For myself, I'm pretty optimistic to have three Hobbit movies. Too often, movie adaptations leave out too much from the plot of the books, in favor of making a simple and striaghtforward (read: dumbed down) story, with characters being rather flat and issues simpler and more black-and-white. So here we have a chance to see a movie that will hopefully avoid that. I'm pretty sure The Hobbit itself can be made into a three-part movie comfortably, though we all know there will be original ideas included as well (Legolas, Tauriel, ...
I admit I'm pretty split on whether The Hobbit should be only the book itself, or include the other bits unmentioned in the book. But the way I see it now, the Hobbit story
includes not just the book (which only tells Bilbo's POV of the story), but all the related elements from the appendices and Unfinished Tales (which I undestand PJ can't use...), and I'm looking forward to see the whole story put toghether.