One of my favorite podcasts at the moment is 'Point of Inquiry'.
I cycle to work, some 16kms each way, each day. Listening to many podcasts on my trial, not only keeps me informed, but also awake. Its a long way, and by Friday, I'm a little bit tired. MMMyeah, some days I pike it and I drive. Anyway, most days, I have a bit of dead-air to fill. I also subscribe to 'In Our Time' from BBC4, which covers immensely interesting subjects in great detail, with a panel of experts, 'The Science Show' from the Australian ABC. Now on podcast. Also ABC's 'Media Report', Rob Kaufman's 'Turn off your TV', and good old 'Vox Populi'.
Working in TV over 25 years, then newspapers, radio, and now Web, I know from bitter experience I cannot stand advertising, worse still is Radio advertising, so Podcasts are just brilliant for cutting to the meat of the program.