I remember being struck by the cover of The Passage by Justin Cronin, a writer I'd never read and it was enough to get me to read the sleeve notes, which in turn was enough to encourage the purchase. It was a fantastic read, and I bought the 2 following books in the series (which were not so great).

It was that the cover reminded me strongly of the visual language of the covers of the 70s and 80s horror novels of James Herbert that led to me picking it up, it wasn't in fact anything much like any of his books (which I enjoyed in my youth) but I'm glad it caught my eye.