Excellent, highly imaginative story. It's the touches of whimsy that really make it for me... all the little details. Reading it again, I'm remembering how much I liked Dumbledore in this first book (compared to how much I hated the secretive old sod later on). Granted, most of the action is confined to the end of the book, with 9/10ths of the thing being an exercise in extended world-building, but it's all done so charmingly I just don't care.