I really like this app and I think it has the potential to be one of those "must have" utilities. In addition to the "wish list" items that "jspectre" notes below, I'd like to see this work with Leopard's Spaces. It currently only shows up in one space (it's a Prefs Pane so you can't add it to the Spaces list). I contacted the developer and they're aware of this limitation and are trying to pry some API stuff loose from Apple so it will work within the Spaces framework.

The developer was very responsive and is eager to satisfy users who submit suggestions.

I'm going to purchase this quite soon. It's quite a helpful and novel addition.