It depends on some rules:
1. What would happen is a zombie bit a vampire? And the reverse? And with werewolves.
2. A long enough war would cause a human shortage. How often fo they need to each eat?
3. Do these werewolves possess higher intelligence or are they more animal like?
4. Can ghosts interact in the corporeal world?
If I assume that vampires are immune to zombie bites, then zombies are out of the picture. If werewolves are also immune, zombies lose.
If humans get basically wiped out, vampires seem to be more at stake since werewolves can have a more varied diet. Unless the vampires have human farms.
Ghosts, in most literature, cannot poltergeist or become corporeal unless they were really strong or had strong emotions when they died. So ghosts can hand around unless exorcised or something.
Given these assumptions, it's a battle between the generals of vampires and werewolves.
My friends have these discussions too.