Vampires and Werewolves...?

Do you like it better when Vampires and Werewolves are allies or enemies? I'm writing a story where a Vampire kills a Werewolf's girlfriend and seeks revenge by killing the Vampire... Would it be better if the 'chase' was a directed hated, just between them, or if the betrayal created an uproar of sorts (more dramatic, of course) between the two species?