Until I read them to Tabitha a year or so ago, I had never read a word of the Narnia chronicles. They immediately became some of my favourite stories. I was obsessed with them until we finished.
We're watching the films now (and Netflix are making them too, apparently!) and they've done a pretty reasonable job with them, but it makes me want to read the books again.
They're some of the most vivid works of fiction I've ever read and, compared with things like Lord of the Rings, remarkably sparing with their exposition considering the payoff.