I lived by a cemetery for about 10 years and creepy unexplained things happened all the time in our house like electronics going crazy or doors opening and shutting on their own. We blamed it on our "ghost" whom I named Fred.
I can't really say I believe in ghosts as I too am Christian and it would kind of go against my beliefs. But who's to say that ghosts aren't actually spirits, be it angels or demons. Or even that ghosts are just strange manifestations of energy unrelated to souls and the afterlife and such?..... Sorry to write a book, but those are my thoughts on ghosts.