It's definitely becoming more popular, but I have had the same experiences as others. No trick or treaters. I live on a main road in London, so that is probably why, my inlaws live in a cul-de-sac and they get a handful of neighbourhood kids each year.
I definitely think it's worth getting your friends excited for it and dressing up. I suggested having a halloween party to my girlfriends in my baby group and everyone was totally up for it. I think it helps that we have babies whom we can channel our energy into. I love babies in costumes!
One big thing I have noticed is that Halloween costumes tend to be traditional - witches, spiders, ghosts, devils. Scary things only. You may get a few princess costumes for little girls, but that's about it. Oh and pumpkins.