I think they’re all equally good; I don’t think there was ever a JTS moment. I even like The Last Battle (so there). But my personal favorite is The Magician’s Nephew.
On the face of it, it’s the least Narnian, of course. But if you read them in publication order, then in a way, it’s the most, since it explains so much. And I love all the elements of it. London in 1900! Mad Uncle Andrew! The ruins of Charn, Jadis in all her glory, the creation of Narnia, the First Joke! And one of my favorite bits in the whole series (spoiler just in case):
[spoiler]“Well, you see, sir, I’m a married man,” said the Cabby. “If my wife was here neither of us would ever want to go back to London, I reckon. We’re both country folks really.”
Aslan threw back his shaggy head, opened his mouth, and uttered a long single note; not very loud, but full of power. Polly’s heart jumped in her body when she heard it. She felt sure that it was a call, and that anyone who heard that call would want to obey it and (what’s more) would be able to obey it, however many worlds and ages lay between. And so, though she was filled with wonder, she was not really astonished or shocked when all of a sudden a young woman with a kind, honest face stepped out of nowhere and stood beside her. Polly knew at once that it was the Cabby’s wife, fetched out of our world not by any tiresome magic Rings, but quickly, simply, and sweetly as a bird flies to its nest. The young woman had apparently been in the middle of a washing day, for she wore an apron, her sleeves were rolled up to the elbow, and there were soapsuds on her hands. If she had had time to put on her good clothes (her best hat had imitation cherries on it), she would have looked dreadful; as it was she looked rather nice.[/spoiler]
So what’s your favorite? I’ve noticed that many people have Dawn Treader for theirs. LWW seems to be the second favorite. And if anyone happens not to despise LB, by all means, say so!