In standard Windows, you can double click the system menu for any window to close the window fast. However with the new Office 2007, there isn't a visible system menu anymore. Instead, Office 2007 uses custom drawn window with the system menu replaced with a huge Office logo button on the top left.
At first I thought the Office button was its own beast and so I would go Office > Close to close the window. However, yesterday I got tired of how long this 2 step process takes and decided to try double clicking the button to see what happens. Lo and behold, my window closed!
So there you have it, double click the Office Logo button to close your Office 2007 application in one swoop.