Since I haven't said anything about this topic yet Ill throw in my two cents. I believe in ghosts yet I do not believe that they would hang out in cemeteries. Ghosts most likely are located in places where a tragic death has occurred, hence the reason for the ghost to hang around. The whole thing about ghosts is that they only linger if their life is taken either by themselves or by the hands of another. Untimely deaths. The only story, make that stories I have heard of a graveyard haunt, takes me back to my hometown of Exeter/West Greenwich RI. The stories of Mercy Brown and Nellie Vaughn. These supposed "vampires" are supposed to be hanging around their tombstones in the cemeteries that they were "killed" in. The thing about this story that is weird is that they weren't murdered... at first. Supposedly they died from tuberculosis and their families and townsfolk reported seeing them after their deaths. To get totally crazy on you guys, due to these reports many people believe that they were not infected with tuberculosis, they believe they were infected with HVV, check out
http://www.fvza.org They exhumed the bodies and found no decay, only that the hair and fingernails had grown unreasonably long and that their veins had begun to show through their skin. They cut out their hearts, which were full of blood, and burned them on rocks next to their grave sites.
::shrugs:: I went to their sites many times as a kid, one was right down the road from my house. We never experienced anything not at night, during the day, on a full moon, on Halloween, nothing. Though now that I think about it, we never went on the anniversary of their exhuming....
...So that went off on a tangent eh?
*edit: I forgot to add, the main difference between these two ladies stories is that Nellie's story is supposedly a case of mistaken identity, and her ghost appears in order to clear her name of this vampire accusation.