The movie is the first exposure I have had to the wonderful world of Narnia and it must have left a very deep impression in me, because not long after I read the entire series of books.
The one thing no one can find issue with is the CGI. It could not have been done better.
Screenplay (along with editing, cinematography and the like) was also excellent, though I cannot compare it with the book because by the time I read it much of the movie had been forgotten. I especially like the unicorn Peter rode in the Battle of Beruna because when you see the far shot Peter's unicorn is the only thing white and it really stands out (I'm not sure why Edmund was riding a Talking horse in the end, though).
The acting was overall quite good, but there were some minor cheesy scenes where I had to grimace.
I have no idea why most people don't really like the music (perhaps it's too LOtR-ish) but it certainly has the correct mood.
The only thing left is make-up, which I don't think there's much to talk about. Overall, I would really recommend people to watch this movie.