When you launch a program its icon appears along that list and mousing over it will give you a preview of what the window looks like. In some cases, you’ll also be able to interact with that program, thanks to "jump lists" accessible with a right-click. These lists include options like skipping between tracks on a music player, or setting status on an IM application.
Media streaming is another big deal in Windows 7. Straight out of the box you can have a hard disk chock-full of content(acquired legally, obviously) and then share that media with other Windows 7 devices on your network, or even over the web. A brief download lets you link a Windows Live account with your Windows account and from there you can use Windows Media Player to send audio and video wherever you like.