I listen to podcasts pretty regularly. In fact, podcasts and iTunes-U probably get more of my listening time than radio.
Here are the four podcasts I listen to most often:
Focus 580. This is better than any of the national interview and talk show formats on NPR (I can't stand to listen to those, because the public call-in questions tend to be so annoying). The calls they take on Focus can also be annoying, but they sometimes aren't, and the hosts, David Inge and Celeste Quinn, are extremely good.
Le Show with Harry Shearer.
Planet Money, on NPR.
State Week in Review on WUIS with iTunes-U.
I also listen to these sometimes:
This American Life.
Brookings Audio Events.
Swarthmore College Featured Events.
The UIS ECCE Speakers Series.
Podcasts from the University of Oxford.
Since I have a 40-45 minute commute each way on days when I ride my bike to campus and back home, I can usually get in a couple episodes each day, and then I often go to bed at 11:00 or midnight and listen to a podcast as I fall asleep. When I'm doing work that doesn't require much language thought (like editing photographs or making a photo album) I'll also listen to podcasts when I'm not listening to music.