I'm on my second read-through of Deathly Hallows at the moment, which I think is a very good book. And I'm contemplating going for a run-through of the whole series from 1 to 7.

After that, I'm thinking of carrying on with Dante's A Divine Comedy. A very good poem, written in the early 1300s, about the author's trip through the 9 rings of Hell. It's inspired a lot of authors since, and has been the foundations for many a good book.