In no particular order
Practical Shooting After Dark - Good info and entertainment, I like Stoeger's sense of humor
Training Group Live - Much more on the informational side, mainly hosted by Joel Park
The History of Rome - I'm up to the Second Samnite War, good listening for repetitive tasks
Revolutions - Covers various revolutions throughout history, working my way through the Russian revolution
Hardcore History - Dan Carlin's history podcast, we should be due for the next installment of Supernova in the East soon
Forehead Fables - Pure entertainment, I think they're funny guys, the John McAfee episode was legendary