I've recently found myself getting tired of my music and listening to podcasts instead. They're great for long rides in the car by yourself.

I think I tend to lean more toward radio shows rather than podcasts (probably because they're more produced and edited). NPR's shows are great:
Radiolab
Fresh Air

Sometimes their podcasts lack structure, but I also like the 5by5 tech podcasts put on my Dan Benjamin. (5by5.tv) I like:
Build & Analyze
Hypercritical
Mac Power Users

Always looking for new podcasts. What are you listening to?

Nerdist podcast-specifically the interviews on Tom Hanks and Larry Kind
This American Life-Definitely listen to the top-listened show: Mike Daisey, and the followup podcast Retraction (Trust me listening to Mike Daisey, and Retraction one after another is a mindf*** to say the least)

Seth Godin's Startup School has been fun. Also, I've always enjoyed all the NPR podcasts - Happy Hour is another one that I like. I have a few more - will post a list shortly.

@Jenny, thanks! I've been hearing a lot of good things about Seth Godin's Startup School. Listened to the first one this morning - really insightful stuff.

Oh, another one I just thought of! I can't vouch for the podcast in its entirety, but Stuff You Should Know by How Stuff Works had a really good episode about How Meth Works. Super fascinating. Definite recommend.

The EntreLeadership podcast is phenomenal. Great interviews with terrific leaders, CEO's, businessmen/women, etc.

@Billy - Actually, someone else had also recommended the How Stuff Works podcast. I need to check it out.

I love to read, so I really enjoy the Guardian Book Club (from my UK days) and BBC Radio 4 Book Club (ditto).

Here's a list that I keep meaning to get into. Some good ones here.

business-opportunities.biz

All of mine of can be found on iTunes (sorry for those not using it)

Gaming- Weekend Confirmed

For my gaming needs I listen to Weekend Confirmed. I've followed Garnet Lee from his days to 1up over here. I used to listen other sites, but as free time whittled down so did my gaming podcasts.

Movies- Keepin It Real, Slashfilm, and The Golden Briefcase

Tech Things- The Drill Down, The Verge Mobile, and The Vergecast

Per @Omar's comment, is everyone using iTunes to listen to podcasts? I haven't done a lot of poking around, but I use iTunes for simplicity and because it obviously works seamlessly with my iPhone if I want to listen on the go. Are there other options? Is anyone using them?

(Sorry if I should have branched off of the previous comment. I wasn't sure if this warranted an entirely new branch.)