If you had sufficient time to devote to full-time graduate school, or just full-time study in the Gentleman Scholar type of framework, what would you study? We are assuming here that you haven’t burned yourself out already on, or sworn a blood oath about avoiding, advanced academic degrees.
I think I’d have to go for history. Probably something technology-centric. I really don’t have any desire to go back to school to specialize my technical skills any more than they already are.