I remember seeing something like this...
"In [an operating system], the most frequently occurring user action is to <open the application the user has just closed; or closed within 5 minutes>."
And I definitely agree! At least when it comes to browsing, my most common and loved shortcut is Ctrl+Shift+T (Reopen closed tab). I love being able to close things I don't need, without worrying if I'll need it again soon, because getting it back is so
fast 'n' easy.
This could be part of the inspiration why there is no UI to close Metro apps...
Not the case for Windows Desktop. I often go through a lot of mouse movements/clicks/hovers/keyboard typing/remembering to launch an application, close it, just to realize I need it again quite soon.
So I really hope Microsoft is paying attention to UI design, and one of the next Building Windows 7 blog posts will be "Improving the UI and user experience: a quick way to re-open recently closed apps/folders/files akin to Ctrl+Shift+T in browsers".
