Animorphs! Oh, man. Those books are terrible/awesome. Terrible because there are, in my opinion, just a few too many of them, and awesome, because everyone ends up almost as screwed up as they ought to be. For a kid's series about heroes, it's unbelievable what she got away with. Man.

A Wrinkle in Time is a classic for a reason. I just read it fairly recently, and it's a lot shorter than I remembered! Still creepy, though.