Well, I believe this question is messed up in the first place. Because most of people work in order to achieve their dreams. A kid who dream to be an army pilot don't dream about it as a job, but as a way to achieve their dream to fly in the freshest planes.
Said otherwise, propose people to be billionaire and then do whatever they want, only few would chose to work.
So, to me, this kind of answer is the best possible : what job (by definition, a way to sustain their life's price) they would like to do.