StarTalk Radio. Get my fix of Neil DeGrasse Tyson since he's never on The Universe anymore. As an aside, this second season of The Universe is nowhere near as good as the first season.
Quirks and Quarks - great general science podcast
Search Engine - Internet and Tech culture and news
Age of Persuasion - Fantastic podcast about.... advertising. Sounds dull, but it is incredibly interesting, and funny. Behind the scenes look at what companies do for your money. I love it, and have nothing to do with the ad business.
Edit - All three are Canadian, so I'm not sure about availability outside of Canada.
Anybody listen to the artofmanlieness podcast? I see it is pretty new. Some pretty good suggestions so far, I am definately going to check out hardcore history.