Now that I'm back to work, I'm listening to my iPod regularly again. I've hacked iTunes with a network of smart playlists to get a randomized playlist that is a mix of my favorite songs that I haven't heard recently, a few songs I haven't rated yet, and a smattering of podcasts.
My podcast list is evolving slowly. I started with all the science shows I could find and added some short general news clips for variety. A lot of the science shows were redundant, just different people's views on the same headlines. I really like "This Week in Science" from Davis. The hosts are a good mix of intelligent and funny and aren't afraid to get into their personal opinions, and can do so without preaching. I also like "Living on Earth" which gets more into environmental issues. Both are great shows, but both shows are way too long. TWIS usually does an interview in the second half-hour that I usually skip. I like their take on the headlines better. Both shows have been dropped from my regular listening because I just don't have that kind of time.
The Environment Report is my top science/environment podcast. Usually about 20 minutes long, they do 3 to 4 stories that are always well researched and produced. The journalists are easy to understand and always engaging. Good stuff.