Just adding another plug for Econtalk. They cover a lot of different topics and invite people that really know how things work. I remember listening to a podcast on the housing crisis and walked away with a great understanding of how it all fit together.

The Hoover Institute and Russ Roberts have a neoliberal/libertarian slant, but he does a great job in inviting people to his program that he doesn't agree with, but he asks great questions and gives them an open forum.