[conanfan]

I highly recommend any of the following:
Little, Big by John Crowley - the World Fantasy Award winning chronicle of a family living in an (upstate New York?) Victorian folly house on the edge of Faerie.
The City of Saints and Madmen, Shriek, and Finch by Jeff Vandermeer - A series of eerie steampunkish tales and novels set in the city of Ambergris, where colonists and native mushroom people live on the brink of war.
Mythago Wood by Robert Holdstock - World Fantasy Award winner set in post World War I Britain, where a son goes in search of his anthropologist father who disappeared in a haunted wood.
The Songs of Earth and Power by Greg Bear - modern fantasy by Greg Bear (better known for his sci-fi) about a young man who is transported to the world of faerie by the music of a modern composer.
The City of Dreaming Books by Walter Moers - I just finished reading this and loved it - the story of a dinosaur who travels to Bookholm, the city of books, in search of the author of the single greatest piece of prose ever written.
Something Wicked This Way Comes by Ray Bradbury - Bradbury's nostalgia laden tale of an evil circus come to a small town.
Momo by Michael Ende - A brilliant fable for the modern era about a young girl who refuses to sell her spare time to sinister Time Bankers.
The Dying Earth, The Eyes of the Overlord, Cugel's Saga and Rhialto the Marvelous by Jack Vance - this one's a close call, perhaps, but Jack Vance's fantastic weird tales about far future Earth where the sun is soon to collapse is pretty much the source for much of the magic found in Dungeons and Dragons.
The Chronicles of Master Li and Number Ten Ox (Bridge of Birds, The Story of the Stone, and Eight Skilled Gentlemen) - Also a close call, because the setting is medieval China, rather than your standard European fair. Touching and hilarious.
Boy's Life by Robert McCammon - A magic realism story of childhood in small town Alabama.
Stephen King's Dark Tower series - Fantasy post-apocalyptic western epic.
The Talisman by Stephen King and Peter Straub - A boy must travel from the East to the West Coast, flipping between modern and alternate reality America to save his mother.
The Dark is Rising series by Susan Cooper - Arthurian fantasy set in modern Britain.
The Chronicles of Alvin Maker by Orson Scott Card - Card's 19th-century alternate American fantasy, loosely based on the life of Joseph Smith, the founder of Mormonism.

And, of course, there's Harry Potter, and its dark, twisted cousin, The Magicians by Lev Grossman.