I don't really care that much about spirits, as the6y mostly don't tend to have a physical or visible form, making it hard to kick their asses.
So, I prefer zombies. Encouters with zombies might be more traumatizing in the sense of 'grandpa?' but then again, I've got a hedge-trimmer to do the rest of my talking.
On a sidenote, wouldn't it be cool if there was this amusement park island thing filled with zombies, and at the entrance you can pick several types of makeshift weapons and armor? That would be great to relieve tension.