Suppressing rueful grin here -- I fled a philosophy PhD to run a startup, and it's shocking how often the degree turns out to be practical -- if not in substance ( higher-order logics, paradoxes of game theory, history of set theory, common fallacies ) then in style (the framework-vs-lib debate is a weird recap of the continental-vs-analytic divide, IMHO.)

Aurelius is recommended reading, but he needs to be cut with some Epicurus. They start from the same position but reach very different conclusions. I like to think of Aurelius as being noneuclidean epicureanism. :)