Oh, yeah -- Ketchum is definitely one of the best (and a really nice guy as well). OFFSEASON is great, as is RED (though RED isn't really horror, it's sure to stick with you for a looooong time). Also check out JOYRIDE, STRANGLEHOLD, and his collection PEACABLE KINGDOM.
My favorite Ketchum novel, however -- in fact, one of my favorite novels from anyone *ever* -- is THE GIRL NEXT DOOR. Perhaps the most brutal thing I have ever read. You *must* get this one.
I have this version, though it's also available in a slightly cheaper trade paperback:
http://store.yahoo.com/shocklines/girnexdoorby1.html
Trust me. You will *not* be disappointed . . . .
J.N.
http://members.tripod.com/~NEWMANATOR/index.html