Thanks for all your answers, the topic raised many things I had forgotten and should have mentioned in the opening post, and the discussion remained, more or less, within the bounds of reason.
Let me say it again. I liked the movie a great deal. I've watched it 3 times already, and intend to see it again.
What I usually complain about movies that are adaptations of books is that, in order to negate criticism, people often tell you that the story had to be "streamlined" or some such thing.
Now, let me understand this. Streamlining means reducing size, right? Like in cutting minutes off the movie, right?
My gripe is that the adaptation could have been better withOUT increasing movie lenght. Indeed, it could have been decreased.
Someone mentioned the falling stair scene, which took a great deal of time, perhaps two minutes or more, and could have been erased so other scenes, that were present in the books and advanced either the plot or characters, could be added. As an aside, a multi-hundred ton piece of rock hitting that stair, full-force, shouldn't have toppled it too?
Other scenes could also be remembered if I was interested in nitpicking carefully.
The point is, it could have easily been better, and that is to say something. A project that consumed the amount of money it did, and which supposedly had the best Tolkien experts working behind it, should have been a bit more carefull with how the story was told. Much of the subtlety of Tolkien's work was lost (specially, at the scene where Bilbo basically turns into a gollum-like creature for a moment. The books mention a fleeting moment of rage, not a morphing of Bilbo's face).
To those that will want to say "accept it as it is, enjoy the work that was done!", I say that I did enjoy what I saw. It's just that the movie was marketed as the ultimate adaptation of Tolkien's work.
And that is something it clearly was not.