Lloyd Alexander has been one of my favorite writers for years. When my nephew showed an interest in fantasy, it was one of the first series I bought him (we now have a tradition that I get him the first two or so books of a new series each Christmas). Prydain has remained a touchstone for all the “journey to manhood/lost prince” books. The Belgarion was almost as good, Harry Potter is more subtle, Lord of the Rings, a different, and much darker version of the mythos, etc. I’ve really enjoyed discussing these books with him–it’s so nice to have someone in the family who doesn’t think fantasy is ‘weird’. Anyway, I would recommend all of Alexander’s books–he’s a deft hand at comic storytelling (I disagree with Helena about the quality of his writing, but hey, everyone has the right to an opinion).
BTW, I re-read The Dark is Rising each mid-winter, which generaly means I re-read them all. They’re a great read on a rainy winter day.