S is for The Secret Garden by Frances Hodges Burnett. I loved this book and read it more than once as a kid.
R is for "Rat" from The Wind in the Willows" by Kenneth Grahame, specifically Chapter 9: "Wayfarers All." When I read this book for the first time, I happened to read a copy that didn't have illustrations, and I think this is a novel that definitely benefits from them.
I'm an aspiring author / illustrator.