I kinda like them all. Since, well I watched Hotel Transylvania and Adventure time and Mavis and Marceline are both AWESOME Vampires. And I like ghosts because they can just scare the pants of of people and..... I don't know my opinion on angels, demons and warewolfs.
Fine, Vampires because they're cool and two of Saffron's tribe at St Unity, the Emos, are vampires. Marceline and Mavis wear hoodies with the hoods pulled up and sunglasses during the day and go around in their normal clothes during the night.