I have tweaked the official Windows 7 wallpaper which was seen running on the machines at PDC 2008. The cool-blue wavy wallpaper now carries the official Windows 7 logo. The outcome is as follows:

1920×1200 (widescreen)

1600×1200 (4:3)

You can get the original version of the wallpaper without the logos from Long Zheng’s istartedsomething.