At this time of the year I always think of the Michael Jackson music video Thriller.  The specific part that comes to mind is when Vincent Price has the following spoken part in the song:

The foulest stench is in the air
The funk of forty thousand years
And grizzly ghouls from every tomb
Are closing in to seal your doom
And though you fight to stay alive
Your body starts to shiver
For no mere mortal can resist
The evil of the thriller!

His fantastic voice and tone just sets the mood for Halloween.  Another way to set the mood around your house is to try out one (or all) of these Halloween themes for Windows 7 from the Microsoft Personalization Gallery.

Eerie Autumn

Bare Trees at Night, Venice, Italy Mysterious Gate with Textured Wall, and Two Bats in Flight Gargoyle on Building at Night
Charles Bridge crossing the Vltava river in Prague, Czech Republic Fog in Copou Park, Iasi, Romania Harvest Moon through Clouds, October 6, 2006, Canada
A Jack-o-Lantern in a Pumpkin Patch, Canada Branches Surrounding Harvest Moon Horse on Cobbled Street, Prague, Czech Republic
Profile of a Crow Full moon covered by a layer of clouds, 31 Oct 2009, Portugal Fruit Bat Hanging from Branch
Mysterious Forest in the Pacific Northwest Pumpkins Owl with Yellow Eyes

Trick or Treat

Halloween pumpkins Haunted Halloween Scary pumpkin and bats
Halloween decoration   Lit jack-o'-lanterns, close-up

Ticket to Fear

Scary zombie Ghostly dead girl with creepy doll Ghost children in graveyard
At Death's door Zombie monster glaring Ghost
Ticket to fear   Children in ghost costumes trick or treat at haunted house