When I think of Halloween, I think of a CLASSIC decoration....the Jack O' Lantern.
I couldn't help but do a little research into the origins of the Jack O' Lantern. This site is a very good read on the who, where, and why of this tradition. I chose this as my "classic" theme as it clearly states:
The jack o' lantern is easily the most recognized and used symbol of Halloween in modern age. Not only is it used outside front doors in traditional form, but it's become the veritable treat container for trick or treaters. While the face of the jack o' lantern has changed over the years with the advent of pumpkin carving kits, it's still an ongoing tradition.