Early on in my career I noticed that the most fun programming seems to be done by people who are not actually trained as computer scientists: mathematicians, physicists, engineers, chemists, astronomers ...etc This sort of numerical computing and simulation stuff is incredibly fun and quite rewarding. You work much more often on core logic and much less often on boring fluff. Of course it is all very subjective and it pays shit. So the answer is: research at a research uni, employed by an applied mechanical engineering lab, but trained as a mathematician.