Madeleine L'Engle captured my imagination way before J.K. Rowling even came into the scene. About 10 years earlier, at least.
It started with Wrinkle in Time which is one of the most amazing books I've read in my youth, with its family of scientists delighting me with their scientific discussions at the dinner table.
After reading that I sought out Wind in the Door, Swiftly Tilting Planet, then the newest book of the series Many Waters.
If you love sci fi books you have to try reading her works. They're just awesome :)