Can't say I've ever thought too much about it- I see the decorations etc being sold at the shopping centre but don't really see any kids getting dressed up or anything. Don't think I've ever had a trick or treater come visit either. I usually forget it's even Halloween.
However although I don't really give it much thought if it ever becomes more popular/ we move to an area where it's more popular or whatever I won't be partaking or let DD partake- similar reasons to what a few have said, I would rather stay away from anything that has to do with the occult in whatever way. Can always do something fun at home instead with other like minded kids if it becomes a big deal! But unless we pack up and move to the US or something I don't think it will be.