I was vacillating on my decision to get Leopard, until I saw this preview. Many of the new features and enhancements wowed me and the people to whom I showed the preview: Time Machine, the ability to put Notes on email, new Spotlight features and Cover Flow, which is a visual way to find your documents.
Cover Flow is one of the best features of the iPod Touch/iPhone interface. I can see where Leopard is going. It's getting ready for a touch screen Macbook! Now I'd like to get a family edition for me and my wife.