Some parents and churches don't like this holiday. They believe that it's "of the devil" so they either don't do anything with it (no candy, no costumes) or they come up with some silly "Christian alternative" like a Fall Festival where they basically do Halloween, but only with other Christians and they outlaw costumes that have to do with witches, monsters, or people beheaded by guillotine.
Here's my take on Halloween.
I would venture to say (by experience) that the vast majority of people who celebrate Halloween don't know and don't care about it's origin - it's simply the "dress up and get candy day". Is the origin of Halloween important enough to abstain from it? I don't think so. You can argue that the time of year and traditions that surround Christmas and Easter have pagan roots.
Think about the major holidays in our country: Christmas, Easter, Thanksgiving, 4th of July. Christmas, Easter, and Thanksgiving are very family-focused events, and rightly so. On the 4th of July, we see friends gathering together for BBQ's and communities gathering for parades and carnivals. I guess you can even throw in St. Patrick's Day, where communities gather for parades and public drunkeness. But there's something unique about Halloween: it's the only holiday where people in your neighborhood open up their homes to each other! Families en mass are walking the streets of your neighborhood, kids are running and laughing, and people are greeting each other. The opportunities for showing hospitality are incredible!
My suggestion on celebrating Halloween is this: just get over the "evilness" of it and use it as an opportunity to get to know your neighbors. Have some fun, dress up, and hit the streets! If your kids are older or you don't have any kids, turn on the porch light, make some hot chocolate for cold parents, stock up on the chocolate (if you want to be really popular, give out full-size candy bars!), and meet people. Strike up conversations. Talk with parents and tell them how cute their kids are (because they really are!). Make Halloween a missional event in your neighborhood. Once you're introduced to people, look for them as they're out and say "hi". Send them a Christmas card. Maybe host a block party or community BBQ when the weather warms up. Don't miss this opportunity to show some hospitality, love on your neighborhood, and build some bridges with people who need Jesus.