I've decided that as a parent I hate Halloween. We didn't take B out trick-or-treating. At three year's old, he doesn't need that much candy, can't even say the phrase, and wouldn't really understand what's going on. But they did have a party at his class, which meant he brought home a bag of candy. I've tried regulating it so he doesn't get sick and it lasts longer, but since he knows it exists he spends way too much time simply begging for candy (currently having a fit on the floor which has lasted nearly half an hour). Maybe when he's older and can regulate it himself (or suffer the consequences) it won't be so bad.
I don't know about regular neighborhoods, but door-to-door trick-or-treating continues to drop in rate since we've been here at these apartments. We got a couple dozen the first year, about a dozen last year, and exactly seven kids this year. This year the complex even handed out fliers to tape to the door if we're giving out treats. I think a big issue is all the safe, community events available. Many churches now hold trunk-or-treating, where everyone brings their car and the kids go around the parking lot to trick-or-treat. Malls are a great place to go, warm and quick, with no danger of questionable treats. The Sandy Southtown Expo Center held a five-day Trick-or-Treat Street. For a reasonable price, you could go get treats there, and participate in the activities, while the money went to a good cause. If we take our son trick-or-treating next year, we'll likely skip the cold and the driving around and simply take him to the mall or one of these community activities.