I like these ones a lot:
-Answer me this (funny)
-The Bugle (funny and makes up for my total lack of current affairs knowledge. Sudan is splitting in half - who knew?)
-The Meditation podcast (good for meditating)
-In Our Time with Melvyn Bragg (good for listening to the occasional episode like when the mathematics professors make his brain melt by explaining imaginary numbers. Plus it makes you feel a lot more clever than you are).
What about you?