Ellen Datlow and Terri Windling have put together a number of fantastic anthologies of adult fairytales. The titles:
Ruby Slippers, Golden Tears
Black Thorn, White Rose
Black Heart, Ivory Bones
Black Swan, White Raven
Snow White, Blood Red
(Pretty much anything either of those two women have ever touched is excellent, by the way.)
Though I think it appears in one of those titles, you might also want to read this spooky little Snow White story by Neil Gaiman:
http://www.holycow.com/dreaming/stories/… (And again, many of his novels are fairy-tale like in nature; Neverwhere would be my first recommendation there).
A YA author I'd recommend would be Holly Black. And if you've got the stamina for it, Susannah Clarke's Jonathan Strange & Mr Norrell is in the top five books I've read in my life.
ETA: If you want any more ideas, feel free to drop me a line. Modern fantasy is sort of my area of specialty...