In short, my question is: I want to keep both my options open once I finish my undergrad degree (being a physicist, or an engineer). Would it be better to go with an undergrad in engineering and a masters in physics or an undergrad in physics and a masters in engineering? In a bit more detail, I am choosing between mechanical engineering and mathematical physics for an undergraduate degree. I think I would enjoy being a theoretical physicist more, but the demand for theoretical physicists are low, and the chance of one getting an awesome job is minute. Right now, I'd rather have a mech. eng. degree because of the work opportunities. But if physics picks up momentum in the next 4-6 years I'd love to be right there in field. Basically, which would be more disadvantageous to me, being a theoretical physicist with an undergrad in mech. engineering or a mech. engineer with an undergrad in mathematical physics?