The Zedcast was my first podcast. It's Canadian (get it? Zed, instead of zee?), and very funny. Most of the other podcasts I listen to were recommended by the Zedcast guy:
-Zee and Zed ("Americanadian" differences by a married couple - he's American, she's Canadian)
-Quirky Nomads (their tagline is "The story of a family that said, 'If the Republicans get any worse, we're moving to Canada.' And then? They really did.")
-The Bob and AJ Show
Then, of course, Sunset and 42nd. And the official Lost and Grey's Anatomy podcasts.
I listen to Sunset and 42nd, the RENT podcast, the Project Runway podcast (no new episodes, obviously, since the season ended), Best Week Ever and Cast Party. I think I might subscribe to the Lost one, too.