Oh, I can list a hundred supernatural fiction books. I think I'll just list the ones that have some ghosts in them.
Dime Store Magic and Industrial Magic by Kelly Armstrong. These are the 3rd and 4th books in the Women of the Otherworld series. I've read 1 (about Werewolves) 2 is also about werewolves and 3 & 4 are about a witch. I think 5 & 6 are actually about ghosts but I just haven't gotten that far to recommend them yet (I know they are about 1 ghost that is in book #4). Ok, I hope this wasn't too confusing.
If you like other supernatural things like vampires, werewolves, witches and mind readers, I can list lots more.
Oh, The World of Darkness released a series of Wraith books. They are the company that created Vampire the Masquerade. I read some short stories about the wraiths but only read the werewolf and vampire series.