Recently in a comment section not quite near you, Lisa Hirsch opined that "A modest and charming book ought to get a modest and charming film."
Well, it's not going to get one.
Early reviews of The Hobbit: An Unexpected Journey have one thing in particular to say about the movie, besides comments on the 48fps: it's loooong. And slooooow.
According to IMDB, the movie is 169 minutes long: that's 2 hours and 49 minutes. That's almost as long as Jackson's Fellowship of the Ring, part 1 of his Lord of the Rings, which in theatrical release (the short version) was 2 minutes short of 3 hours. According to the reviews, Jackson's Hobbit part 1 covers the first 6 chapters: that's almost exactly one-third of the book. Although the original 3-movie plan for The Hobbit was to have the third movie cover events between The Hobbit (which takes place first) and The Lord of the Rings, it now appears he's just splitting The Hobbit up into three movies: the taglines for the sequels on IMDB correspond to the plot that way.
If the two subsequent movies are the same length, the totality will be 8 hours and 27 minutes. More likely, it'll be longer: Jackson's LOTR sequels were longer than his first one. (Meanwhile, Tolkien's successive volumes were consecutively shorter, if you exclude the Appendices.) If The Hobbit movies increase in size at the same ratio that the LOTR movies did, the total will be about 9 hours, plus or minus 15 minutes, depending on whether you take the ratio of the theatrical versions or the extended editions.
The Hobbit in the standard paperback is 273 pages of text (287 - 14 forematter). In the same edition, the three volumes of The Lord of the Rings total 1283 pages if you exclude the Prologue and Appendices, 1442 if you don't. That's approximately five times as long a book, but it didn't get five times as long a movie.
The Lord of the Rings movies, then, worked their way through the book at an average rate of between 1.88 and 2.58 pages a minute, depending on the page count above and whether you use the theatrical or extended editions of the movies. The Hobbit, meanwhile, is proceeding through the book at the stately pace of between 0.49 and 0.54 pages a minute, depending on how long the three movies turn out.
Now comes the interesting part, and trust me, I've worked this out with a calculator. If Jackson had gone through The Hobbit at the same clip that he proceeded through The Lord of the Rings in its theatrical version - already a massively slow undertaking by movie standards; the four-hour Gormenghast miniseries ran through its two huge volumes at nearly 5 pages a minute - it'd be between 105 and 120 minutes. Even at extended edition rates it'd be no more than 145 minutes. (At Gormenghast rates it'd be over in one hour.)
But! What if he'd filmed The Lord of the Rings at the pace he's filming The Hobbit? (If he'd filmed it at Gormenghast rates the entire thing would have been 4 1/2 hours - just right for the two-movie version he'd originally intended.) Determining the answer depends on both whether you're counting the Prologue and Appendices as part of the book, and on how long you expect the three-part Hobbit to turn out, but the answer would be somewhere between 40 and 49 hours. Ye gods.
Some of the Hobbit movie reviewers say that only Tolkien fans will enjoy something that slow-paced. They're wrong: only the most devoted Peter Jackson fans will. One of the frequent defenses of the LOTR films is that Tolkien fans would only be happy if they got something that was days long and had everything from the book in it. This time we're actually getting that. I don't expect to like the prospect.
From the length alone, I'm expecting this movie to be Jackson's Phantom Menace, the most tedious blockbuster I ever saw. Maybe it will induce equal cringes of embarrassment in the movie-maker's fans, and maybe the movie will slink away in shame and we can forget about it, like we eventually forgot about Ralph whatzisname. That would be the happiest outcome.