My podcast list just took a nosedive thanks to work toughening up the regime on nights. Talk about depressing. Now I have to find something else for my mind to do while my body's busy.
My favourite serious podcast is
This American Life which often looks a bit boring, but rarely disappoints when you listen.
Plenty of
Radio4 stuff has been mentioned already, so I won't repeat those, but I also record Pick of the Week on Sunday evenings and Loose Ends on Saturday evening on my PVR, then convert them for my phone.
For anyone with even a passing interest in the financial world (which ought to be everyone in these "interesting" times) the
Planet Money podcasts are fairly short and sweet. But if you like a bit of tinfoil style reportage from the USA, the
Patriot Trading guys are hard to beat... as long as Eric's there. As a one man show it's far less entertaining. Radio4's
Money Box output is much more useful though. As is
DH Unplugged for a conversational, US-centric overview of the week's financial markets. Andrew Horowitz does a few others shows which are useful if you're interested in trading. I haven't found an equivalent for UK trading.
Gaming-wise the
Giant Bombcast is good is you need a bit of company for up to three hours, but I prefer
Gamers With Jobs, though I've learned to distrust a lot of their opinions. They are a lot more easily impressed than I am.

Good bunch to listen to though. As are the
Epic Battle Cry team. Then there's a load of console-oriented stuff on
IGN if you're bored. Finally there's
PCGamer for those of us who haven't got used to these new fangled console things..
Tech-wise,
PC Per does a pretty nerdy 'cast which is useful, but a bit dry/technical. And Ryan Shrout sniffs a lot. I think I prefer the
Tech Report stuff and
Maximum PC, which can be a bit more rambling and entertaining.
The
TWIT network's already been mentioned. Leo Laporte's an easy voice to listen to, but there's a lot of what I'd describe as tech gossip on his shows rather than useful information for any "average" geek. This Week in Tech is probably the only show I'll keep listening to now I'm not getting paid to listen.
PCPro, obviously. And just for general gaming/tech/bitchy chat the extremely un work-friendly
Widget Show is worth a listen... when they can be bothered to record a show.
For science I like Radio4's
Material World and
Quirks & Quarks.
Mmm... I think that's enough from me. Especially as I'm now even more depressed that the vast majority of these have got to be culled from my weekly listening. :-/