The biggest hit last year was the chocolate amaretto fondue with sliced fruit (strawberries, bananas and pineapples) for dipping. I did placards for all the food with appropriately Halloween-oriented names. Can't remember what I called the fondue, though... Oh! And, of course, the "Vampire Punch", which was a sangria that really packed... well, a punch. I was really surprised how well it went over.

I'm still tinkering with this year's menu, but so far I have:

Crackers & Spinach/Artichoke dip (Mold dip)
Chips & Salsa (blood clot dip)
Buffalo Wings (bat wings)
Deviled eggs (monster eyes)
Finger sandwiches (um... finger sandwiches)
Sliced fruit with cool whip/cream cheese dip (Organ cuts and dip)
Chocolate covered strawberries (piped chocolate to make chocolate covered spiders)

And some recipes from perfectentertaining.com:
Baked monster eyes (mini tacos baked in mini muffin tins)
Pus Stuffed Peppers (jalapeno poppers)
Bleeding cupcakes (chocolate lava cakes)