Stephen King's The Stand or Desperation.
The stand is one of my all-time favorite books, though pretty lengthy, and Desperation was a great read.
TS is about a disease that wipes out almost everybody in the world, it focuses on a small group of survivors who are having dreams about a small farm, and they feel compelled to go to it.
Amazing book, but only if you can stand about 1100 pages.
Desperation is definately up there on my list, I'd have trouble explaining the plot of that one without giving something away, though.
Other books I really enjoyed:
Salem's Lot (Vampires)
It (Evil clown- Insano long)
Insomnia (Starts off pretty slow, but it really picks up)
Misery (Sadistic fan holds her favorite writer hostage)
The Dark Half (Hard to explain, think Evil Twin/Tumor)
The Dead Zone (Great book, a guy gains the ability to read minds)
Carrie (Psychic girl, goes insane, kills some folks, and very short. Good book.)
Kujo (Rabid dog terrorizes a mother and son, decent book, but nothing too amazing)
The Talisman (A kid goes on a quest to recover a talisman that could save his mother's life, good book)
Dark Tower I through V (A very good fantasy series, but Stephen's ego starts showing in the later books)
Yeah, I'm a Stephen King fan, but you've got to be careful with him. He's written amazing books, and terrible books. I love the guy, but I think he needs to retire, his new books are poorly written, and his ego is really flaring.