One of the more exiting new features for some notebooks and other devices will be auxiliary displays. A video of a laptop featuring such a display was posted at Channel 9:
Next year there will be a new feature available on some laptops and Tablet PCs: auxiliary displays. This lets you do some things on your computer without needing to open up the computer and wait for it to start up. See what this new feature is. There's more information on the developer opportunity here on the new Windows SideShow page.