Being an NPR junkie, I love DLing and listening to the podcast for Intelligence Squared, that way I don't have to listen to all the ads. Do wish it was unedited though...
The only other podcast I have ever really cared about is the Official Lost Podcast, those things are sometimes more entertaining than the actual show. I have almost wrecked my car from laughing so hard while listening to it while driving (not a good idea).