I've come to really like Word 2007 and the other Office 2007 applications. While the Ribbon toolbar took some getting used to, I know find it to be much more intuitive than the old Word toolbar. For those having difficulty or are afraid to upgrade to Office 2007 because of the Ribbon don't be dissuaded: think of it this way – we spent years being trained by Microsoft to use their old non-intuitive toolbar, with Word 2007 we have to 'unlearn' these bad habits.

There have been changes to Word 2007 one of which is that switching between open documents isn't as easy as it used to be. Another big change is that when you clicked the "X" in the top right corner it not only closed the open document but Word as well.I learned to use the"Close" command from the Office button at the top left, but hadn't thought about a keyboard shortcut until I was checking DailyRotation this week and came across Rick Broda's PC World post Close a Word 2007 Document without Closing Word You can also check thi out on The Industry Standard website here.

According to RIck:

"… just memorize a keyboard shortcut. Both Ctrl-W and Ctrl-F4 will close the current document without closing Word itself. No fuss, no muss." 

What a great and simple tip to make working with Word 2007 easier