Anything by Bentley Little. The Collection is a great anthology, with two of the best stories being THE WASHINGTONIANS, where we learn the Founding Fathers were sadistic cannibals, and history professors protect us from the lunatics with wooden teeth who keep the secret, and The Colony, where an incoming President learns we're secretly still under British rule. His novels kind of follow a formula, that of "What if X were run by Satan/monsters/demons?" I recommend starting with The Resort or The Store for a good intro. He has the Stephen King seal of approval, which ought to be good enough for anyone.