Posthumous Podcast Awards
Not strictly RPG but close enough - Podhammer: For years this was THE show for Warhammer players. Based in Australia it was unflinchingly honest about the state of the game, the state of the armies, and the state of the players. The show was always a blast to listen to. It faded out a couple of years ago and though it does appear there have been some restart tries the last entry is January of this year. Maybe one of these days it will rise again.
Current Favorite Podcast
A superhero rpg, comic book, superhero show & movie podcast it is very casual and often recorded during the main hosts lunch break. BAMF is the one podcast I somehow find time for every week. It has a wide range of interesting guests from all over the U.S. to Canada to the U.K. from indie comic book writers and artists to game writers like Steve Kenson and Christopher McGlothlin. Game-wise it has mostly focused on M&M and ICONS but other games are welcomed too - Supers, Bulletproof Blues, and After Earth have all made appearances recently. The show is very laid back but manages to stay focused most of the time and typically runs around an hour per week. If you're at all interested in super-stuff it's worth a listen
Honorable Mention - Know Direction: It's THE Pathfinder podcast. It's a little bit of a mess as there are a bunch of sub-shows covering different topics and the hosts sometimes rotate between them but the main show is solid and they consistently have access to both Paizo and independent writers behind various Pathfinder books.
Semi-Relevant Bonus Podcast for Online RPGs - Massively OP Podcast: If you want a good survey of what's going on in online gaming this week, the Massively OP Podcast is my favorite stop. usually about an hour it is a news and discussion show hosted by the writers and editors of the Massively OP site. There are game-specific podcasts for many games out there but for the big picture this one is the best.