I just switched to Windows 7 and I'm enjoying the new taskbar functionality. When you mouse over an icon in the taskbar, it will show all the documents/windows that are open in that program, by display a thumbnail of each window
It's very useful when you have several webpages open at once. This is one of the big new features in Windows 7 and commonly known. What I didn't know is these thumbnails are dynamic. I was waiting for a render to finish and I hovered over the vegas icon in the taskbar and the thumbnail actually showed what was going on in Vegas, the preview window was animated in the little thumbnail. Pretty cool.