While not as well known as the Brothers Grimm, Charles Perrault's Mother Goose tales predates the Grimms by more than a century. Perrault's tales were a mix of original stories, expanded versions of folk tales, and reworkings of earlier tales. Many of his stories ended up in the Grimms collections.
One tale that the Grimm's did not also include is Toads and Diamonds. Heather Tomlinson's version sets the action in pre-colonial India, where the diamonds come with many problems and the toads are a blessing in disguise.
Another one is Hop O'My Thumb, which Jean-Claude Mourlevat retells in The Pull of the Ocean (translated from the French by Y. Maudet), setting the tale in modern day France.
I could probably do a week's worth of Cinderella retellings. While this is a tale that has versions in many, many cultures, Perrault's was one of the first published ones.
Cinder by Marissa Meyer has a cyborg for a main character and is set in a futuristic New Beijing. The first of a series, the next one, Scarlet comes out next month and retells Red Riding Hood, another Perrault tale.
Just Ella by Margaret Peterson Haddix looks at what happens after Cinderella, when a maid has to learn how to be a princess.
Ash by Malinda Lo tells what happens when Cinderella decides the Prince is not who she wants to end up with.
Throne of Glass by Sarah J. Mass features a Cinderella who is also a trained assassin. (The adult comic book series, Fables will appeal to older teens. Its Cinderella is a spy that kicks so much butt she gets her own spin-off series, Cinderella: From Fabletown with Love.)
Another favorite fairy tale that was first published by Perrault is Sleeping Beauty. Sadly, I know of only one retelling that includes the bit about the Prince's mother being an Ogre (The middle grade novel, Twice Upon a Time #2: Sleeping Beauty, The One Who Took the Really Long Nap by Wendy Mass. And it doesn't include the bit where she eats the children.)
Briar Rose by Jane Yolen sets the story in the Holocaust.
A Long, Long Sleep by Anna Sheehan is sci fi, with a Sleeping Beauty that was put into stasis and forgotten about.
Castle Waiting by Linda Medley is a graphic novel about what happens to the abandoned castle after Sleeping Beauty goes off with her prince.
Spindle's End by Robin McKinley features a tomboy princess who's intent on saving her, and her village, herself. (Also be sure to check out McKinley's version of Beauty and the Beast, Beauty.)
We still have Wilhelm Grimm's birthday in February, so there are more to come, but what are your favorite fairy tale retellings?