Well, an imagineer, first of all. That's the end goal when I finish animation college (character design, storyboarding... ).
But if I were to be a castmember, I would probably want to work in the Animal Kingdom, as a caretaker for the reptiles or fish. I'm sure there is a much better official title for it, but that's where I would like to be. That or working at the seas pavilion at EPCOT.
If not, a portrait artist would be a fun job too.