(2) Another bit to look for, presumably from the second (or third) film: in the artbook's entry on Gloin, there's reference made to an exchange between Legolas and Gloin in which, seeing a miniature Gloin carries of his wife, the elf asks "Who is this ugly creature?" (ART AND DESIGN, p. 64).
(3) The biggest scene referenced in the filmbook but not in the film has to be the Old Took's party, which is mentioned (and illustrated) twice: on page 22-23 and 30-31. Dan Hennah, longtime Jackson stalwart through all the Tolkien films and Production Designer of the new HOBBIT movie, himself played Bilbo's grandfather. Here's how the scene is described in the ART AND DESIGN book (p. 30):
Gandalf and Bilbo first meet when Bilbo is just a little lad at the Old Took's party. It's a midsummer celebration in the orchard near the lake, put on by the Old Took for the children with a Punch and Judy show, fireworks and beer for the parents.
Gandalf plays a little trick and pulls a dragon out of his sleeve. All the other children run away, but Bilbo stays and is intrigued by the dragon, giving Gandalf the impression of a rather courageous little hobbit. And of course it was fun for me, as I got to play the Old Took!
. . . we had one day shooting . . . with Little Bilbo, his mother Belladonna, Old Hob, Old Gammidge and Bilbo's grandfather, the Old Took. They have a little chat over a drink when Gandalf arrives -- quite a nice scene actually. It was very picturesque with hobbits outside under a tent enjoying a half-pint, young girls dancing, a bit of colourful magic that set the scene for later events.
Maybe the filmmakers felt that opening the movie with three flashbacks was one flashback too many. Or maybe it'll be in an extended cut. Or maybe, as I suspect, it'll be in the second film as a flashback. Time will tell.
(4) Finally, there's a sequence which did appear in some trailers (where I mistook it for Dol Guldur) and gets its own spread in the ART AND DESIGN book (p. 149-150): The High Fells, also known as the Tombs of the Nazgul (a name that irresistibly reminds me of the old DOCTER WHO episode Tomb of the Cybermen). It's rather nice to learn that one feature of these tombs was based on a passage in the Great Pyramid.
Aside from these, the HOBBIT CHRONICLES: ART AND DESIGN book (text by Daniel Falconer et al, Weta/Harper Design, 2012) is well worth getting in its own right. as the record of a team of artists' attempt to capture Tolkien's world in two-dimension. Two-hundred-pages of art, much of it sketches by Alan Lee and John Howe, plus explanatory text of what they were trying to achieve in a particular piece or sequence. At times the explanations were beyond me (as when the costumer used technical terms for fabrics and patterning and treatments ("distressed"). Other bits were clear, and interesting, as the passing comments about how they used Art Deco motifs for the dwarves and Art Nouveau for the elves of Rivendell (p. 51 and 136, respectively), about their attempts to retain each dwarf's iconic color (p. 37 and 67; I missed it, but apparently it shows up in the lining of their hoods), about their initial intent to have the dwarves bring their musical instruments to Bag-End -- concept art for some of which is shown, complete with travelling cases (p. 49), before Jackson decided (like Tolkien before him) that it was a bit odd for the dwarves to be carrying viols and the like on a desperate quest and the instruments were dropped (aside, I think, for a recorder flute -- Bofur's I think (see p. 69) -- which I remember seeing in a later scene. In short, they were, as at one point they neatly put it, "pursuing an aesthetic" (p. 196). Hence some changes, like the to my mind rather unlikely depiction of Goblin-town as composed entirely of scaffolding (where did they get all that wood? I kept thinking to myself. From some vast, previously unknown underground forests?), were made for purely practical reasons: "There's nothing more cinematically dull than a big dark hole in the ground" (p. 168). Similarly, forgoing the absolute pitch darkness Bilbo encounters when lost under the mountains was done in full recognition of the fact that "Lighting in caves is always something of a cinematic cheat" (p. 186), yet "The Hobbit is filled with scenes that take place in the dark" (p. 189).
A few comments or observations were simply amusing in their own right. I'd been bemused by the listing for "horse make-up" in the closing credit, but this book explains it. They'd carefully chosen out shaggy ponies for Thorin and company, only to discover when they were filming in the summer that these ponies shed their extra hair in summer. Not men to be put off by such things, Jackson and Hennah concluded that "The solution was to put them in hairy suits with wigs, so they ended up in make-up and hair just like the human cast!" (p. 15). And I was much bemused by the observation that "if New Zealand's landscape was cast in the role by location scouts, it also had its share of make-up and prosthetics" (p. 111), which seemed to sum up the way they used and transformed actual landscapes nicely.
Two things described, or at least mentioned, in the ART AND DESIGN book that I totally missed in the film were (a) Ori's boardgame and (b) Grinnah the Goblin. The boardgame is shown on p. 59 and described as a dwarven version of fidhcheall or gwyddbwyll, the game Arthur and Owein play in that weird tour-de-force in the MABINOGION, "The Dream of Rhonabwy". Perhaps it's packed away in little Ori's baggage and will show up in the second or third movie(s). As for Grinnah, if he was ever named or is still to appear, I certainly never noticed any goblin being called out under such a name -- but then again, with so much going on, it's easy to miss one character among the multitude.
Finally, the ART AND DESIGN book comes with two nice added bonuses: a foldout copy of Thorin's Map with the moon-runes printed in glow-in-the-dark lettering, and a facsimile of the movie version of Bilbo's Contract. And yes, I did test it to see if the glow in the dark moon-runes wd actually appear, and can confirm that they do. Or maybe the moon was just in its right phase last night for when my copy of the book was printed . . .
current reading: THE TWELVE CLUES OF CHRISTMAS, a "Royal Spyness' novel by Rhys Bowen 
*The most disconcerting thing about this was that it turns out the final cut of the film sometimes used slightly different takes than the trailer, so sometimes I saw scenes using different bits of film from what I'd already absorbed from the trailers.