Well, this is completely off the topic of video games podcats go, but as long as we're plugging good podcasts, I'll join in. My favorite by far is
Dan Carlin's Hardcore History. I hate the name, but whatever...It's very well-produced, theater-of-the- mind type look into various periods in world history. He has a way of describing historical events that really bring them to life, and I like that he often touches on many aspects of history that you probably wouldn't hear in a traditional history class.
The only problem with it is that the down time between episodes is 2 - 3 months on average.
He's currently wrapping up a series on the German-Russian front in WWII called "Ghosts of the Ostfront." Excellent, excellent stuff, but the brutality described in the podcast is hard to take. It opened my eyes to how difficult it was for the average Russian soldier and all the people who were caught between two horrible, monolithic, despotic regimes. He also points out the crisis of conscience that some (only some) of the German soldiers and commanders were having during that time.
If you're an amatuer (very amatuer) history buff like I am, there's a lot to appreciate there.