The next version of Windows, said to be Windows 8 has been already in discussion with lots of leaked screenshots of development builds. Although nothing much on the OS is known yet, we might get more clarity in the coming months. Meanwhile, Windows Valley has created a neat theme for Windows 7 users called the Windows 8 Theme which comes with the leaked logo and tagline. The theme has 4 wallpapers and custom sounds enabled.
The 4 wallpapers are set to change every 30 minutes, which can be customized.