Superdave, you're a turd.
I think people beliefs about ghosts are similar to those of religion - some believe, some don't. I totally agree with Roxy here too that a large part of it has to do with how open the person involved is. And even those who do believe in the basic idea of ghosts, believe different things at different levels regarding fortean matters.
And between Roxy's liquor cabinet and Frooty's abuse of alcohol and breakfast cereal... maybe we should start an AA group that can clean up pigeon poop.