This is a tired subject. How sad it is that every October sincere Christians need to give reminders to their fellow believers on the evils of halloween...
Regardless, I did just that in a Toastmasters speech today. I gleaned much of my material from the following website:
A Puritan's Mind
Bottom line...reject this evil holiday. "Reformation Day" is a much better "alternative" (if such a thing is needed):
Reformation Day 2006