Rich Roll – Interviews with random, inspiring people asking in-depth questions, usually focusing on veganism, health, making healthy mental or physical changes, what it means to succeed, and what it means to be fulfilled. Or, just people with interesting life stories. He's very LA, though.
(It's turning into a cliché that I will recommend a RR podcast to you at some point, but his podcast covers a lot of topics.)
Sean Carroll's Mindscape – Science, society, philosophy, culture, arts, and ideas.
(My other podcast addiction.)
Myths & Legends – Humorous take on mythology. It's fun. I usually know the myths he tells, but his way of telling the stories is entertaining.
Between The Covers – Literature.
Complexity by the Santa Fe Institute – Science, philosophy, sometimes arts.
I listen to others, but those are the core ones.