I subscribe to about 25 podcasts, all of which I listen to. Some are too weird to mention (Waller FM, I'm looking at you) some are accessible enough for my girlfriend to happily watch with me (Diggnation). And some are such bloody obvious choices you should be sectioned for not listening to them already (Crave, BOL, TWiT, Cranky Geeks).
But I've got four favourites not mentioned above; four podcasts you should really try out, because they're so good they're rumoured to cure leprosy.
A critical and accessible podcast for casual fans of space, space technology, space explorations and the universe. Presented by Fraser Cain and Dr Pamela Gay, an assistant professor of physics at Southern Illinois University, Edwardsville. Probably my favourite non-tech podcast after following on from a previous favourite, Slacker Astronomy.
Stuff You Should Know -- (Warning: iTunes link)
Highly entertaining and accessible weekly show from HowStuffWorks.com, explaining every topic under the sun from 'Are humans wired to survive?' and 'How blood pressure works', to 'What happens if we run out of water?' and 'Are Nazi war criminals still at large?'
Stephen Fry's Podgrams
Stephen Fry is to brains what Chuck Norris is to fists. Even questioning his logic and mental prowess has led to dementia and death. His 'podgrams' are sporadically published but remarkably entertaining, and some of the most perfectly thought-out opinions, on topics such as the world of broadcasting and why he hates dancing, ever published to the Internet.
The Ricky Gervais Show
About as intellectually stimulating as watching a shaven chimp fling fecal matter at children, The Ricky Gervais Show features the inane ramblings of one of my favourite unknown geniuses, Karl Pilkington. "Neil Armstrong, that spaceman, he went to the moon but he ain't been back. It can't have been that good." Yeah, that was one of his. You have to pay for the show, but it's only £2.95 for the whole of series 5, which is an epic bargain.