I voted for The Voyage of the Dawn Treader. I liked that book a whole lot. I still like the LWW, but it just isn't as good as The Dawn Treader. I really don't know exactly why I like it more, I just do.
On another note, I read them in chronological order, but I think that reading them in published order would be better. I'm a Star Wars geek and I love their series, especially how they saved the mystery of how Darth Vader became, and I think that the Narnia series did something a lot like that.