I cycled through a lot of things, but, I think my earliest dream for a career was architect. I'm not too far off today actually, I'm studying engineering. Though, you wouldn't catch me anywhere near a civil engineering/architecture class nowadays. I'm going to specialize in Mechanical Engineering.
I realized that building a house in minecraft is one thing, but laying out floor plans is another. A tedious tedious task, especially if you're forced to use pencil and paper.
After the architect thing, I thought being a theoretical physicist would be cool, but then I remembered I barely have the aptitude for Calc let alone some of the crazy crazy stuff they do.