A quick list of the ones I listen to:
SMODcast (w/Kevin Smith and Scott Mosier) [if there was only one podcast I listened to it would be this]
I Love Movies with Doug Benson
The Rick Emerson Show
Cort and Fatboy
The Adam Carolla show [the preceding three are all radio shows; two local(a lot of pop culture humor), the last national; talk radio without the commercials or breaks of music is awesome due to podcasting]
The Lost Podcast with Jay and Jack
"I assure you, whatever the others promise to do, when it comes to the showdown, they won't be there."