The trick, I've learned, is to assure oneself quite firmly that the candy is being purchased for trick-or-treaters. This alleviates any sense of guilt that may come from the fact that one now has enough sugar to put a hummingbird into a diabetic coma. I've also found that making cookies for someone else helps, as I use some of the candy in the cookie dough. This is my favorite cookie recipe at this time of year:
Chop up ~ 2 C of your favorite halloween candy. I don't recommend mars bars, as they tend to melt and stick to the pan, but M&Ms, reeses cups, snickers bars, etc. all work very well.
1 C butter, softened
1 C brown sugar
2 eggs/egg replacer equivalent
2 tsp vanilla
1/2 tsp salt
1 tsp baking soda
2 1/2 C flour
Blend. Add chopped candy and mix until the candy bits are more or less evenly distributed.
Bake at 350F for 10-15 minutes, or until just browned.