Speaking of LotR, I have seen RotK twice so far, and I thoroughly enjoyed both times. The last 20-30 minutes seemed to drag on the first time I saw it, but it does work the second time around. The performances were more than adequate all around, and, like a good western, the landscapes were as much a part of the story as the acting. Josh has a lot of good comments on the many criticisms really big Tolkien geeks. That does not mean, however, the movie is completely without criticism. For instance, this article criticizes the movie not for the acting, but for the script and how Frodo is portrayed in the movie. Frodo in the books is able to resist the ring's temptations right up to the point they enter Mount Doom, where the ring very suddenly takes over. It is shocking to those who first read it. The movie removes that sudden shock. Anyway, the article makes a better case than I could. By the way, even with that flaw, the movie still rocks.
Continuing on this theme, a Tolkien scholar chimes in on whether old Ronald would have liked the movies. On top of that, an interview with John Rhys-Davies on the movie and politics. Both links provide good stuff.