Spooky – either The Association or Atlanta Rhythm Section
Ride of the Valkyries - Wagner (a little tangential, but suggestive of thrills and violence)
Masquerade Waltz - Khachaturian
Montagues And Capulets from Romeo And Juliet - Prokofiev
“Bad Things”, by Jace Everett (The theme to True Blood
Baby Did a Bad Bad Thing – Chris Isaak
Psycho Killer - Talking Heads
Riders on the Storm - The Doors
Shotgun - Junior Walker
Gotta have something by Here Come the Mummies; in honor of the season, probably Bump.
Right song, but I’d go for the version by the Bonzo Dog Band. The lead singer sounds much more deranged.
Zombie Creep - The Papaya Kings
Scary Monsters - David Bowie
King Of The Monsters - Man Or Astro-Man?
Evil Plans Of Planet Spectra - Man Or Astro-Man?
Murder By Numbers - The Police
Clap for the Wolfman - The Guess Who
*Devil Man * - Hipster Daddy-O
The Howling - Hipster Daddy-O
Astro Zombies - Hipster Daddy-O
Search and Destroy - Iggy Pop
Locomotive Breath - Jethro Tull
Aqualung - Jethro Tull
Look! No Head! - Laika & The Cosmonauts
Brain Damage - Pink Floyd
Welcome To The Terrordome - Public Enemy
Paint It Black - The Rolling Stones
Sympathy For The Devil - The Rolling Stones
*I Hold Your Hand In Mine *- Tom Lehrer
Masochism Tango - Tom Lehrer
Roland The Headless Thompson Gunner - Warren Zevon
Werewolves Of London - Warren Zevon
“Born of the Night” by Midnight Syndicate (actually, pretty much anything from any of their albums qualifies, but that one’s my favorite)
You can cherry-pick stuff from a few compilations, like:
A Nightmare Before Christmas - The Jack 2 Pack
Halloween Classics: Hellbent for Halloween
The Rocky Horror Picture Show Original Soundtrack
A History Of Horror, by the City of Prague Philharmonic
Just about anything by the Necromantix
the True Blood soundtracks are awesome
And, inspired by the OP’s username: Summer Breeze by Type O Negative. Creepy as hell and awesome all at the same time.
Black Magic Woman by Santana
The Purple People Eater by Sheb Wooley
Ghostbusters by Ray Parker, Jr.
Welcome to My Nightmare by Alice Cooper
Mysterious Mose by Rube Bloom and His Bayou Boys
With Her Head Tucked Underneath Her Arm by Rudy Vallee
Great suggestions!
Holy Modal Rounders: The Werewolf
Doctor John the Night Tripper: Gris Gris Gumbo Ya Ya
Roky Erickson: Night of the Vampire
The Cramps: TV Set
–There are certain artists who works offer many possibilities…
Or go high class with Dead Can Dance…
Tubular Bells
Yeesh. I stayed up a bit past bedtime compiling a list of my own, since I was noodling around looking for a few things for this thread anyway. I started one last year but there wasn’t much on it. Now I have 12.5 hours worth of Halloween themed music. I think that’s enough!
Concrete Blonde - Bloodletting (the vampire song)
My friends 
Dr. Smith have recorded the perfect Halloween song.
(Everyday is) Halloween - Ministry
It’s just not Halloween without “It’s Halloween” by the Shaggs.
Also, “Danse Macabre” by Saint-Saens.
Grim Grinning Ghosts by Thurl Ravenscroft.
Blue Oyster CUlt’s “Joan Crawford” (she’s risen from the grave, in this one)