Those are good points you bring up, Samwiseb.
I have never read Hunger Games, but the movie itself felt like a completed story. It didn't seem open ended enough to warrant a second movie, so I guess I don't know exactly where the book goes from the movie version's conclusion.
As for The Hobbit and LOTR....well, from everything I know, all Peter Jackson did was basically pull a Stanley Kubrick and just "followed the books" (a la Kubrick's take on A Clockwork Orange), so it wasn't a matter of "interpretation" or "reverence" it was just, "let's keep it simple and follow the books". So I think Jackson is a bit overrated in his field. I will say that yes, the stories themselves as told in movie form are very compelling, and the King's coronation scene near the end of RotK is damn near a tear jerker....I think I owe that more to the performers of the scene rather than Jackson's directing.
If Jackson is going for some expansion on the Hobbit book, that is going to be interesting to see. In truth, again, he's only the director...it's the screen-writers who are the underrated souls who have to adapt the story for expansion into a trilogy, unless, as Roysten pointed out, the three films are going for 90 minutes run time a piece, as opposed to three hours per with the LotR trilogy.
In any case, I do think it is fitting that The Hobbit somehow does get expanded or adapted into a trilogy. As I said before, I don't think fans of the films would be happy if they waited some ten years for just "one more movie."