The costume I remember best from my little-kid days was not one of my own but that of a classmate. He dressed up as a hippie and carried a sign that said "Send Batman to Vietnam!" It was the sign that made the outfit. Perhaps he got the idea from this comic.
Of course, in my little-kid days, Halloween was about the candy. My brother and I were instructed to eat our Halloween hauls slowly over a couple of weeks. But our parents shouldn't have allowed us to store the bags under our beds. It was too easy to sneak sweets.
In junior high and high school Halloween was more about fashion and horror creation. One year I helped scare kids who came to the door of my friend Louise's house. Another year I played a corpse in a cardboard coffin. Some of my friends and I had been granted the use of a classroom at the local grade school to make a scary house. We constructed a giant papier-machete spider with glow-in-the-dark-eyes and a portrait painting that spurted blood. Vampires Karen and Don guided groups of kid through the various exhibits. After they had described my terrible death, I would suddenly sit up and yowl. This worked well until my movements nudged the coffin off the radiator and onto the floor. Wow, that hurt. But I stayed still, and Don said, "Well, she's dead now."
Then there was the year I went to a Halloween party dressed as a Star Trek style alien. I put green eyeshadow all over my face. I won best costume at that party.
Nowadays all sorts of elaborate Halloween paraphernalia is available, and Halloween parties can be lavishly staged events. Steve described one such party he attended where horror-themed stuff covered every inch of house and grounds. There was a corpse floating in the pool. Inside, a selection of meats had been laid out in the shape of a corpse. I suppose this Halloween intensification could mean something or other about our society, and if I think of any relevant sweeping statements, I'll post them.