Personally, having read all 7 books, (though not in a long time) I thought Narnia was great as a movie.

I enjoyed it thouroughly.

Watching it, as I did LOTR, I found myself thinking that many things were just as I would have imagined them to be. Granted, they cut the end part a bit short because of time, but other than that I thought it was quite good.
edit: Thankfully, alatar, PJ did NOT.