This is another classic in King's list. It's Dracula, moved up to the 20th century and into your living room. Scary stuff.

As an aside, I loved the character of Father Callahan, and was absolutely thrilled to find him pop up in the Dark Tower series (around book #3, if I remember correctly,) although the two stories have little else to do with each other. By that time, King had started to intentionally inject his other works into the Dark Tower mythology and vice versa, creating a truly interesting web of fictional boogery.

Any way, if you're interested in a fun and exciting vampire story from before vampires became en vogue, check out Salem's Lot.