I listen to:

This American Life: humorous stories that are certainly curious to think about. They have a very humanistic spin on life but the storytelling is great anyway.

Table Talk Radio: the only Lutheran radio game show where the points are like 6th grade class status. Hosts are great characters but I wouldn't recommend this if you don't know much about Lutheranism/Christianity.

In Our Time with Melvyn Bragg: learn something new each week on topics ranging from literature to philosophy to mathematics and science. Panelists are great at discussing and the host, Bragg, always keeps the conversation going.

Irish and Celtic Music Podcast: because who doesn't like it?

Concordia Ed Tech: because I'm a teacher and they've got great tips about educational technology.