I listen to mostly programming podcasts, namely:

• Hanselminutes (RSS)
• Stackoverflow (RSS)
• Herding Code (RSS) – My favorite by far
• Software Engineering Radio (RSS)
• .Net Rocks (RSS)
• Polymorphic Podcast (RSS)
• Deep Fried Bytes (RSS)
• Selected items from from IT Conversations (RSS)

Non programming related include:

• BrainStuff (RSS) – These are very short (2-3 minutes)
• Stuff You Should Now (RSS)
• Astronomy Cast (RSS)
• Think Vitamin Radio (RSS)
• Science Talk (RSS) – Scientific American