Clicking on the icon in the top-left of every window produces a seldom used menu, whose sole purpose is to be familiar to Windows 3.1 users. It made sense to do this in 1995, but in 2009 it's time to move on...
In the "Ribbon GUI" Windows 7 applications, Microsoft have also illogically moved the menu button from being in the top-left. The top-left was ideal in Office 2007 because you can reach a corner of the screen very quickly with the mouse (see here http://blogs.msdn.com/jensenh/archive/2006/08/22/711808.aspx for an interesting article on this). Therefore, this "Windows 3.1" menu in the top-left of every window is wasting valuable mouse area!
The typical Office 2007 user under Windows 7 would have the following functionality with the Office app maximized:
mouse to bottom-left: start menu
mouse to bottom-right: show desktop
mouse to top-right: close
mouse to top-left: program menu
I really think that Windows 8 should update the window-icon menu in the top-left of every window to be more functional than at present - i.e. it should take place of the blue menu button (the "application menu anchor") from the "Ribbon" interface in standard Windows apps (though not necessarily including the additional "ribbon" tab interface).
The top-left window icon could take one of two possible forms:
1. Still be the icon of the particular program in use (NOT like the ugly Office 2007 icons in the office orb, and NOT circular), except larger, and with an enhanced "Menu" functionality. They could perhaps indicate that this is a special button by also adding a small drop-down arrow symbol to its right.
2. A standardised blue button like in Windows 7 Paint or Wordpad. The Program icon is now moved to the centre-left of the window title. The window title is now centred.