It's sort of a binary question, I think--if you're in a low-density job like "neurosurgeon," it's neurosurgery. If it's a high-density job like "Marine rifleman," it'll probably be something other than your basic job description. For variable density jobs, which could be anything from "rank and file code monkey" to "RMS," it's a true conundrum.

For the record, I'm still not sure of the answer, nor what I want to do when I grow up, although I'm enjoying network security.