The City in the Lake, by Rachel Neumeier

I haven't read a good stand-alone fantasy novel in a while. The City in the Lake, by Rachel Neumeier, is like a fairy tale, though not based on any one we are familiar with. She takes elements of fairy tales, though, and weaves them into her story. It's beautifully written, and a more sophisticated read than (dare I say it) the Harry Potter books. I would say readers 12 and up would enjoy it, if they have a more advanced reading comprehension level and want to read something a bit more complex than Percy Jackson's books (which are still fun to read).  Also check out Neumeier's The Floating Islands.