Spirits, Anyone?

I'm in the middle of Madeleine's Ghost by Robert Giradi and it's very good. It's about a guy who's cheap New York apartment is haunted by a spirit in distress, and strangely there is a romantic comedy movie opening today with Resse Witherspoon with basically the same initial premise, though I doubt this book and that movie can even be remotely close to each other in quality. What I want to know is, do my readers believe in spirits? Have you been haunted, physically? I am haunted by the dead, but only in a mental way. There are also three spirits in the book I'm working on currently, in the tradition of A Christmas Carol, one of my all-time favorite stories.

Also, Halloween is my favorite holiday.