THE INHABITED WORLD: A Novel, by David Long (Houghton)Read about another book on the list.
"This beautifully written ghost story is a moving speculation about the world beyond. A man wakes up to the realities of having dodged just about every stand he could have taken and, 10 years after his suicide, realizes that he's at another branch in the road. If he can't intervene in the world of the living, perhaps the living world can help spur him on to do what he needs to do."
Also see James Hynes' 2008 top 10 list of Halloween stories and Brad Leithauser's five best ghost tales.