ZombiesRot & Ruin, Dust & Decay, and Flesh & Bone by Jonathan Maberry
I'm not a huge fan of zombie books, but this series is great--the author created a cast of memorable and diverse characters, made the logistical rules of zombie-hood believable, and above all, retained a sense of humor throughout. Plus there's tons of edge-of-your-seat action.
General Scary TalesThrough the Woods by Emily Carroll
This one's got the added bonus of being a graphic novel--a wonderfully spookily illustrated graphic novel. It's a series of dark fairy-tale-like stories that will bring to mind the scariest parts of the stories you know--the big bad wolves and the Bluebeards and the creatures under the bed. It was a Cybils finalist a couple of years ago. Don't read it at night...
Edgar Allan Poe's Tales of Death and Dementia illus. by Gris Grimly
A graphic novel featuring several of the classic tales by Edgar Allan Poe. Definitely de rigeur Halloween fare. This one was a Cybils finalist, too.
Red Spikes by Margo Lanagan
*Shudder* Dark and scary short stories. And this is not her only book of such tales. They are SO GOOD, though.
Vampiresroundup of fun vampire books some* (*many) years ago. Neither of us is what you would call a vampire enthusiast, but we've got a handful that come highly recommended. My favorite is always going to be Sunshine by Robin McKinley. But we wrote the the roundup so long ago that it doesn't include a few later fun ones, like Sarah Beth Durst's Drink Slay Love and Kimberly Pauley's Sucks to Be Me.
GhostsThere are way too many good ghost stories to list them all here, so I'm just going to focus on a couple of SERIES that I really enjoyed, the better for you to binge-read in bed until you've missed Halloween and then you get up and realize it's December. Just kidding.
The first two books are The Name of the Star and The Madness Underneath, and if you're a fan of anything set in London, you'll want to check these out. Ghosts! Jack the Ripper! Mysterious deaths! It's good fun.
Gilda Joyce by Jennifer Allison
This is an incredibly fun mystery series suitable for younger readers, full of humor and strange happenings, and headed up by the irrepressible Gilda Joyce, psychic investigator extraordinaire.
WitchesTexas Gothic and Spirit and Dust by Rosemary Clement-Moore
These are so, so good--funny and scary both. (Sensing a theme in my picks?) If you like the Southern Gothic genre, you'll want to pick these up. I didn't even know I might like the genre, but if Rosemary Clement-Moore keeps writing them, I'll keep reading them. The books relate the intricate and supernatural adventures of the Goodnight clan, in which witches and ghosts and ne'er-do-wells abound.
Enjoy a safe and spooky Halloween!