Love His Dark Materials. I thought the third one was slightly un-focused, but overall - fantastic series. (IMO, though, Pullman appears to have had only one series of that quality in him; the rest of his writing doesn't begin to approach that level.)

I suppose HDM really is the anti-Narnia. And Lewis would probably fall over dead if he read it (assuming, for the sake of the argument, that he was at least briefly not dead). Another reason to love the books, that is.