Look at this crazy stuff!
Right now I've got a pretty sweet graphic design gig where I sit at my desk all day and work at my computer. It has afforded me the chance to become acquainted with MANY podcasts. Until I can think of something more interesting to put in this space, I'll give you some suggestions (in no particular order and NOT divided into categories):
The amazing show starring James Randi, Apologia, The Atheist Experience, Atheist Talk, Buzz out loud, The Dharmalars Lost Podcast, Dogma Free America, Freethought Radio, Geekscape, The Geologic Podcast, Just Not Right, Grammar Girl, Another Goddamned Podcast, Astronomy Cast, Mindcore, The Polyschismatic Reprobates Hour, The Jay and Jack Show, the lost podcast with jay and jack, Legal Lad's quick and dirty tips for a more lawful life, The Transmission, Modern Manners guy, The Non-prophets, Nova Science Now, Ockham's Razor, Point of Inquiry, Real Science, The reason Driven Podcast, The Infidel Guy, American Freethought, The Secular nation podcast, Indesign secrets podcast, design tools weekly, Science talk: the podcast of scientific American, Skepticallity, Skeptiod, the skeptic's guide to the universe, Starkville's "house of El" podcast, The 10th wonder podcast, Strongbad email, 60-Second psyche, 60-second Science, the bible geek, smodcast, evolution 101
That's all I can remember right now.