One of the things I tried ages ago was pressing the Window key and each other key on the keyboard. Call me strange if you like.
Under build 5472 of Vista on my Toshiba I got clumsy and hit [Window] [Pause] (they're next to each other). It opens the Windows system-properties dialog. That got me to experiment with some other combinations. [Window]  , [Window]  , [Window]  , etc open the first, second, third items on the Windows quick launch toolbar.
Now I've got to go back to XP and see if it was there all along.
The fact that Eileen has just blogged about something very similar shows the serendipity fairy has been busy again.