The book 18 books ago that impressed me was Hershel and the Hanukkah Goblins by Eric A. Kimmel and Trina Schart Hyman. But it's a Caldecott Honor Book, so there's that.
I'll tell you what has impressed me book-wise lately (though it's not a book at all):
The Fantastic Flying Books of Mr. Morris Lessmore.
I saw this little charmer quite a while before it won an Oscar for Best Animated Short Film. It was free on the internet back then (this post was in draft mode, with the embedded video, but now that it has won the Oscar, the video is no longer embeddable). Now you can download it for $1.99. I promise you, it's worth your time and money. You can't tell from the trailer, but it's a really sweet story. Plus, it won an Oscar, so there's that.
Does this mean I just need to stick to award winners?