I'm with you Encaitare, they totally screwed up the HP the movies. And don't even get me started on the characters in LotR, take Elrond for example, not only did he not look right his entire personality was different. Elrond was one of my favorite characters in the books, and he was so wise, but in the movie he was just some jerk! And what about Faramir, in the books he was much wiser than his brother and there is a contrast between them, but in the movie the difference is almost insignificant. There is a lot more but I am not going to get into it right now.
Also, I think they are making a movie or a mini-series of the Legend of Earthsea which is second only to Tolkien in my book, but they will probably screw it up.