I'm also a Tolkein fanatic. I found the first movie not all that bad. Although some of my favorite parts were edited out (i.e., the Old Forest and Tom Bombadil), and there were some substitutions/changes that I didn't think made much sense in the context of the books (from minor things like Arwen vice Glorfindel rescuing Frodo at the Ford of Bruinen to Elrond coming across as a weinie), my only real complaint was relationship between Isengard and Mordor (Saruman was NOT allied with Sauron - he was a puppet). Galadriel's speech wasn't bad - almost the way I imagined it - and the passage through and battle in Moria was excellent, IMO.
The second movie, OTOH, really pissed me off. WTF elves showing up at Helm's Deep? How did a bunch of Aragorn's kin turn into elves? Theoden as a wimp??? Faramir taking the Ring to Osgiliath?????? Puh-leeese. Finally, the entire way the movie dealt with the Ents was pitiable. Still, the battle at Helm's Deep was nicely staged. And Frodo's passage of the Emyn Muil and the Dead Marshes was just as I had pictured it.
The third movie does redeem some of the ground lost in the second. It appeared to follow closely the Return of the King. My only deep complaint was they cut one of the truly dramatic scenes from the book: where the Nazgul steps through the shattered gateway of Minas Tirith confronted only by Gandalf just as the cock crows and the horns of Rohan sound across the Pelannor. Now THAT should have been kept...
Overall, the movies were okay - excellent special effects, very good characterization of the main characters, awesome battle scenes. Aside from the "True Believer" (
) quibbles, the movies are probably the best possible rendition of the books that you're ever likely to see.
On the upside, it was the movies that convinced my youngest daughter to decide to read the books - so that was a good thing, IMO.