Podcasts are great for keeping up to date, getting new ideas and generally helping you to feel connected with the rest of the geek community. Much less effort than reading a book, particularly with subjects that you're not even sure you're interested in yet, and you can listen to them on your way to work.
The quality of some of the podcasts out there is truly fantastic. Here's what you'll find on my iPod:
.net General Programming
.net UI and UX
General Software Engineering
Technology News
- PRI's The World: Technology - Not just another latest gadget show. This one covers things like innovative use of technology in the third world and how technology is effecting politic and vice versa.
http://www.theworld.org/technology-podcast
Non Programming (but still essential for the well rounded programmer)
That's all I can manage on my commute to work. If you've got any suggestions let me know and (if I like them enough to subscribe myself) I'll add them to the list.