I love thrillers. Esspecially when there's plenty of mystery to it. ESSpecially when it includes hauntings. But not cheesy. Long, long, LONG, big, FAT book kind.
Anything by Stephen King. He focuses on root fear, the monster under your bed. The specter hiding deep within the recesses of a crumbling building. Even the power struggle against good and evil.
Or anything close enough lol