I'm so into podcasts right now that I rarely listen to music in my car or home anymore. Personally, I like the more scripted podcasts, I don't like the ones where the host or guests talk about whatever and meanders from subject to subject. That said here are some of my favorites:
Slate's Culture Gabest - is beyond brilliant. It's one of the few podcasts I listen the day it airs. It's smart, funny and the subjects range from low to high culture. I love it. See a review below...
Wait Wait Don't Tell Me - is a hilarious quiz show about the past week's news events. I think it's NPR's #1 podcast.
Theory of Everything - Is a strange eclectic podcast, where each week the nerdy host will take a theme and explore variations of that theme. Trippy Weird Esoteric
Decoder Ring - Another great Slate.com podcast. It's about cracking cultural mysteries and tries to figure out what it means and why it matters. My favorite so far was the podcast about the history of paper dolls and how two very young gay brothers from the midwest became obsessed with them in the 1950s and how their obsession continued into their adulthood; one to fame, the other to oblivion.
Risk! If you like This American Life, The Moth, Snap Judgement this podcast is like them but way, way dirtier. The host is a gay comedian named Kevin Allison, who I hadn't heard of before and to honest, he's kind of annoying. He's Mr. TMI, like letting us listeners know he's into Asian bears and fisting, and preferably Asian Bears that can fist him (talk about a small demographic.) But each week you get everyday people sharing funny, embarrassing and sometimes gross-out sex stories they thought "they'd never dare to share in public".
You Must Remember This - IMHO is the best source of Hollywood history in the podcast universe. The hostess is an absolute genius, she an almost academic approach to her research, findings, and correlations. And YES her old-timey voice is/was horrible, but her computer-generated narrater was worse. And as someone up thread said, I think she mentioned on her series finale that she no longer going to be doing the podcast. But if anything, give it a try and listen to the series on the Manson murders and their ties to Hollywood. Chilling.
For those TL;DR types: listen to Slate's Culture Gabfest!!!!!!!!!!!!!!!!