Let me preface with this: I have to drive upwards of 600 miles a week, so I listen to a lot of podcasts.
I listen to Joe Rogans podcast every time a new one comes up. If you're not listening to it, you should be. Not all comedy, not all UFC, not all evolution and aliens. It all depends who his guest is for that particular show. Really interesting and entertaining show, I dig Rogans' committment to any project he's doing, and he's very passionate about comedy.
His sidekick "Redban" is growing on me too. Couldn't stand him when the show first started.
Other comedians I dig:
Louis CK - Love the new Louis show and he's a standup beast
Mark Maron - Dig his Podcast "WTF"
Doug Benson - Keeps it light and current, has a fun little podcast called "Doug Loves Movies"
Freddy Lockhart - Pretty damn funny, gets nostalgic about the 80's and 90's as well as old school hip hop. His podcast is called "Whats' Good"
Jay Mohr - His impressions are really good, and he's really quick. Comes off as a cocksucker but his podcast is revealing he's not really that big of a dick... Anymore. It's called "Mohr Stories."
Greg Behrendt - His comedy is waning, but he's the original "Ripped Like Jesus" and "crybaby spiderman" guy. He has a podcast called "walking the room." You can get away with listening to him and his co-host Dave around episode 8 when they finally figured out the audio.
And, believe it or not, Greg Proops. He's an assasin, a straight killer. Knows his way around the English language and is a literal Machine Gun, whether its' ranting about the goverment or knocking down a heckler. He does live podcasts and they're pretty great. It's called "The Smartest Man in the World"