I liked the movie, but I have to say that re-reading the books last year was a mistake. Like Puke mentions, I wind up spending most of the first viewing wondering about the differences, or trying to remember where we are with regard to the book. I find it very distracting.
Anyhow it was pretty cool. I liked the Ents, but when the movie was over, Denise (my wife) said "It was a good movie, but I could have done without the talking tree" lol oh well.
During the showing that we saw, the theater was full of kids. It turns out they were all from a local private school; "Rivendell School" which according to the woman sitting next to us, was so named because the founders were fans of the books. These kids turned out to be a great audience though, because unlike ANY other audience in the DC area, they didn't chatter throught the whole movie. In fact, they were so totally into it that they would burst into applause on occasion (In fact, Legolas seemed to have his own cheering section. I think Orlando Bloom might be "Dreamy" by Jr. High School Girl's standards). In fact, I would go so far as to say that the audience actually added value to my viewing, as opposed to detracting from it.
-Sik