Windows Phone 7 influence.
Even if you're not looking at it with Apple products in mind, there is a clear convergence happening between smartphones, tablets and the traditional desktop and laptop form factor.
Just like how Apple is integrating iOS elements into Mac OS X 10.7 Lion, Microsoft seems to be borrowing bits of Windows Phone 7 for Windows 8.
Uncovered on Within Windows is what is tentatively the welcome screen for Windows 8. See it below:
The background image is one of the pieces of artwork included in Windows 7. The actual image is changeable, but what is said to be set is the time, date, power controls and ease of access. There's also talk of being able to control music playback from the lock screen, which would be handy for when a PC is used as the music player at a party.
Different variations of Windows 8 may have different welcome screens. For example, tablet devices may have pattern-based unlocking instead of ctrl-alt-delete.