I would not even rate it as one of Disney's "good" movies, let alone greatest. Perhaps I'm alone in this, but I found the movie dull and uninspired. It all felt like I'd seen it before in Lord of the Rings...and the much better BBC versions of the Chronicles of Narnia. Yes, the effects were good, yes the acting was fine, and yes overall the film was okay, but that's really all it was for me. I walked out of the theater feeling like I'd kind of wasted those two hours because it was all just uninspired retreading of familiar grounds.
Just because a movie is financially popular does not make it a great movie. Fantasia was a financial flop, as were Pinocchio and Alice in Wonderland when they were first released. I would argue all three of them make Narnia look like a home video. In fact, I would argue EVERY Disney animated film blows this film away, including Atlantis, Home on the Range, and Treasure Planet.
Actually, the more I think on it, the more I realize why those films are all better than Narnia - heart. I didn't feel anything for any of the characters. The whole thing was cold and unfeeling, though the child who played Lucy almost managed to save it.
Don't get me wrong - I wanted to like this movie. I taped all the making of specials as I have done for every other Disney movie, and I was there opening night, eagerly hoping to have a new film to add to my DVD collection in 6-10 months. However, I have no intention of buying this now when it does come out. If anything, I may buy the BBC version instead...or just watch Lord of the Rings again and save myself some money.