Virginworlds.com podcast, focused purely on MMOs. Comes out every week without failure, and Brent sometimes does special midweek shows. Think of Gamingsteve, except only MMOs. This is a small, relatively unknown podcast with about 800 regular downloads, but you wouldn't know that from the quality. The website recently celebrated its one-year anniversary, but the podcast hasn't been going on for the whole duration.
The Widget. "Games, Tech, and Whatever." It's currently undergoing some major changes. They stopped doing the podcast for about a month, but now they've decided to do a series of podcasts with different hosts from different locations that just come out whenever they can. The ones before the change were absolutely hysterical, and the new ones aren't half-bad either. I imagine once they get on their feet and get into the groove again, it'll pick up in quality to where it once was. It's pretty well known, I'm surprised it didn't make the list. I believe they have about 80,000 downloads.
GamersHell.com weekly podcast. Comes out every week, without failure (this week they're taking a break, though). This is very light on discussion, being mostly scripted. It reports gaming headlines, new releases, and contains game reviews and other nifty stories now and then. It's fairly short, always falling under 30 minutes. It's very funny, and well-made.