Coraline, by Neil Gaiman
Neil Gaiman describes "Coraline" as a "fairy tale in the same way that Hansel and Gretel is a fairy tale". It's twice as terrifying too; in H&G all the witch wanted to do was eat the kids, not kill them and drain their souls into wispy husks. I've read quite a few anthologies of horror and "Coraline" beats them all hollow.