Matilda by Roald Dahl
I'm an upper elementary teacher at heart, so don't roll your eyes at me! Stevie made me buy this at Powell's when we were there last week. I think that maybe I read James and the Giant Peach as a kid, but other than that my Roald Dahl experience is next to nil. I've read many parts of the BFG because it seems like every fourth and fifth grade class reads that and when I was substituting I read it aloud a lot.
Well, I'll tell you what - Roald Dahl creates great characters. Kids love outlandish situations. Take anything ordinary, say an overly strict principal, a bad home situation, a sweet teacher, a precocious kid, and then exaggerate it and kids will eat it up.
(By the way, I found two typos in this version of Matilda, and although it may seem really uptight, it truly bothers me. Who's not getting paid well enough to edit children's books?)