Halloween Without A Costume

I have been thinking a lot about what I want to be for Halloween lately. I am having a party so I assumed that a costume is a must.
I tossed around the idea of being Queen Gorgo from the movie 300, and as badass as that character is, the costume just doesn't have enough "flair" for me. And then I thought I could be vampire, but all the vampire costumes I could find were lame. And then I found this amazing witch's hat with feathers, tulle, and sequins, but I decided that was too played.
So what if just didn't have a costume? What if instead of dropping fifty dollars on a costume that is hardly worth it, I just wear something fabulous but creepy at the same time? Something I already have in my closet. Or maybe use this as an excuse to go out and buy something fabulous and creepy. So I've been looking around Polyvore.com to get some ideas. And I found some very good ones.