'Hardcore History", Dan Carlin gets a thumbs up.

Since 2006 Dan Carlin's "Hardcore History" has dived deep into pivotal points in human history. Originally aimed at the history nerds this podcast is not for everyone. However, if you want an intriguing take on historical Tipping Points, "Great Men of History" and the true long term cost of the human condition this podcast is a must listen. As a former Radio Host and reporter Dan Carlin has a great voice and tells his tales in a way that grabs even a passive listener.

This podcast is long and may take several sessions to get through but it is well worth an extra lap around the parking lot.....

Dan Carlin's Wikipedia Entry
Dan Carlin's Website
Dan Carlin's Hardcore History on Podcast Alley
Dan Carlin's Hardcore History on iTunes