This was kind of a hard choice, since I like so many of them, but I finally voted for
Lucy. I love her childlikeness most of all. She loves Aslan with all her heart, and they have such a beautiful, trusting relationship. She's valiant and brave, yet not violent or hardhearted. She's always been one of my favorite characters in literature, not just the Narnia books, and I look up to her as one of my fictional role models. C.S. Lewis knew what he was doing when he came up with her character.
My second choice would be Jill. In the Silver Chair she gets annoying at times, but I love her bravery in The Last Battle.