.NET Rocks has a huge collection of hour long episodes (currently 204) which seems to be mostly interviews. Then there are Polymorphic Podcast that is smaller but has a lot of value to it (not just the show but the show notes with links and source code). Each, in it's own way is a good resource to keep track of the .NET world.
Another one is the Software As Shes Developed podcast which I haven't gotten into listening to yet. It's described to be about "Web/Ajax, Usability, Programming (Rails/Java/OO), Patterns, Agile" which are certainly interesting topics.