Rogue Amoeba introduced a new app recently called Farrago. I'm giving it a shot right now --- if it fits my use cases I'll be writing it up in more detail. For now, I'll say: it's a soundboard app geared toward broadcasters (or podcasters) with a slick keyboard-navigable interface, extensive customization, and a complete organization toolset including sound banks and sequenced lists with sounds and notes for planning out shows.
