I wrote once about podcasts when I first discovered them, but that was a while ago, and I was recently asked for recommendations. I'm always discovering new podcasts, but here are my current favorites.
NPR podcasts a bunch of stuff. My favorite of theirs is the Most Emailed Stories, a daily hour of stories from each of their programs, including arts, science, politics, or whatever is hot.
I almost always enjoy Ira Flatow's Science Friday. This program covers a range of topics, each in a separate episode, in case you're tired of hearing about weather phenomena, for instance. The show often covers current issues. Lately, it's been the space shuttle, hurricaines, evolution, influenza, and stem cell research. I like this program because they have knowledgeable guests speaking in lay terms about the importance of recent scientific discoveries and issues.
Although I don't read Slate online, I enjoy their podcast. It's usually an essay commenting on anything--politics, sports, media, technology....
Also, I just found the Serenity podcast, in case you're interested in that. I haven't heard it, though.
Surprisingly, I haven't found many old-time radio show podcasts. The Radio Adventures of Doctor Floyd is "family friendly", meaning it's appropriate for kids, but also appeals to adults. It's the continuing story of Dr. Floyd and his assistant, Dr. Grant, and their endless task of preventing the evil Dr. Steve (and his sock-shaped assistant, Fidgert) from traveling through time and space to steal historically important items and selling them on Ebay. It's silly, fun, and educational.
This is completely random. Fly With Me is a commercial pilot's podcast about flying airplanes. Each episode he interviews polits and flight attentdants about a particular topic. For instance, a recent one, "The Recognition Edition", was about the special ways that some passengers have thanked their pilot or flight attendant. It's kindof a feel-good show.
This one's a little embarrassing. I don't watch General Hospital anymore. I don't even care what's going on. But I was searching for podcasts and saw one called "Guiding Light". So I wondered if there was one for my old soap. And there is. This guy started watching GH with his wife, and now he's addicted, and for some reason he wants to share it with all of you, with his explicit commentary. He's still working out the format, and I don't expect this to interest anyone else. But when I listened to the first episode he invited emails, so I sent him a little constructive criticism... which he read on the Oct. 15 episode. So now I'm famous.
These are way new. I don't have a video iPod, of course, but I can still download them and watch them on my computer. There aren't very many, and most of the ones I've seen aren't worth watching. I did enjoy Creative Mythology, a blog-type podcast from a filmmaker. He does a lot of muppet stuff, including movie reviews by those old guys in the balcony.