I love putting some creepiness into the holiday season. It's not about ghouls and ghosts and Frankenstein--we did that almost two months ago. It's about putting vintage and world market things into your holiday.
Take for instance this gift bag above. I got it at Cost Plus World Market for $2.99. You can't beat that. It has a definite creepiness-heck, I think nutcrackers are scary and freaky! It says to folks "this is coming from your friend who sees the world in an unsettling way."
Import/Old World looking items are fantastic for setting a traditional holiday mood. I know some people who decorate with besoms (witches brooms) and other old New England items to get an historic feel with a metal pot over the fireplace grate and an old fashioned popcorn popper used over the fire. On my Christmas Tree which is decorated with all colors of metal balls from gold to silver to bronze to copper, I also have ornaments--but only ones with meanings. I have a Viking ship and a Scottish bagpiper, a Virginia is for Lovers keychain, reindeer, and a few Halloween items to represent me, a Jack O'Lantern and an ornament I made to represent the local ghost hunting group I adore, "MVD Ghostchasers."
For more mood, you can take old photos (like the one above) and scan them. Print them out in black and white and decoupage them onto a little oval wood tile you can buy in the craft store. Decoupage with 1 part water to 3 parts glue and brush it onto the surface, put the photo down, then brush it atop of the photo as you smooth it out. Screw an eye hook into the top of it for hanging and you're done. If you use old family photos and do them in black and white, you can have a very nostalgic tree. You can also find things like old-fashioned looking lanterns and hurricane lamps at import shops and even at craft stores like Joann. Candlelight is the ultimate spooky feel, as are fires in the fireplace, and lights on dimmers. Honestly, I have a neighbor who likes to play opera on her home stereo and that to me is the ultimate moody feeling.
I suggest looking to the Victorian era and also the countries of your roots. When I was growing up, we did Norwegian Christmases. We would make paper woven heart-shaped ornaments and straw reindeer and hang them from the tree with live candles--yes! It's hard to believe we survived my childhood. Actually, we lit it on Christmas Eve when we had Smorgasbord and opened our gifts. Santa's gifts were the only ones on Christmas Day and all us five kids slept in one room together to be certain no one snuck out to peek.
During the year, keep in mind when at flea markets and antique shops to look at items as potential ornaments and you'll find yourself discovering many creepy and fascinating things that can add an Old World/Historic feel.
Have a happy moody atmospheric holiday!