5) Unity Previews
In the Ubuntu Unity desktop, when you get a file, you get a lens that automatically open the file in the appropriate application. So, for instance, if you click on a document file, LibreOffice will open it, if you click on an image, Shotwell, will pop it open for you and so on.
What’s new and improved in Ubuntu 12.10 is that you can now right click on files. Besides the usual more detailed information for the file from doing this that you get from most operating systems, you get a ”Preview Pane” for its content type. For instance if you right click a song in Unity’s Dash display, you the album artwork and music player controls. This is a handy little feature.