I've never dressed up for Halloween, because it was never part of my childhood. It has only been the last 10 years or so that some kids have dressed up and gone trick or treating in my neighborhood. Just as well, I would have felt it rude and awkward to beg strangers for candy. Don't get me wrong, I have always loved candy and chocolate, but the not accepting candy fro strangers rule was one that always made sense to me, and I would find it cheeky to ask for it.
I can only remember dressing up twice. The first time I was 5 and we had a dress up party in daycare. I wanted to go as a pirate, but my mother didn't find any suitable costume so she dressed me up as a flower instead and thought I was so cute. I was really unhappy about it. I didn't want to be cute, I didn't want to be a flower.
The second time was for school, one of the last days before some holiday, probably autumn break. I was dressed as a mouse, which was fine by me. I never got to school though, because I felt sick and threw up on the way there.
I used to have customs as a kid (Indian, dog, Viking, vampire fangs) and played with those, but never dressed up for anything besides just playing.
Some years ago one of the TV channels here sent a few horror movies on Halloween. I loved that, but it was only that one time as far as I can remember. I wish they did that again for us horror fans!