For myself, I think it's quite wise to have a day in which we can recognize fear and evil (in whatever form, whether we believe they're actually real or not) and thumb our noses at them.
[And the whole costume thing is awesome, of course.]
If we here in the USA actually treated Halloween like that, as a dare rather than as a celebration (in a sense) of fear and of evil things, maybe I'd be more inclined to celebrate it myself.
Nothing wrong with candy or costumes or ghost stories (and here's a link to a lovely Halloween Op-Ed piece written by Neil Gaiman), certainly. And may you all, however you view it, have a happy and safe evening.