In the past, I've said that I didn't "get" podcasts. Mostly, I said this because most of the podcasts at the time were poorly edited, so you'd have vastly different audio levels, even within the same podcast. Other times, the podcasts just weren't very interesting, and in some cases seemed to exist solely to give the author the chance to tell inside jokes and pat themselves on the back.

However, over the past few months I've found several podcasts that I really enjoy and are very well done, and I thought I'd highlight those:

Programming
Polymorphic Podcast (.NET)
Hanselminutes (.NET and General Tech)
Ruby on Rails Podcast
CocoaRadio (Mac/Cocoa)
Code Sermon (General)

Business
StartupNation
Venture Voice

Tech
This Week in Tech