OK, so until we can get Microsoft to change the default margins in Word, here's how to do it on your own. It should take no more than twenty seconds and just a few clicks of the mouse. I suggest setting your margins to .75", which will save an immense amount of paper over the long haul, but still leaves you with a little bit of space on the sides. For those of you on the metric system, I'd recommend setting your margins to 2 centimeters, which is just over .75".
On your WORD screen, go to FILE, then PAGE SET UP.
Click on the MARGINS tab, and fill in your desired settings. Then click on the DEFAULT button (it's on the bottom of the Margins tab). You'll be offered "Do you want to change the default settings for the page set up? This change will affect all new documents based on the normal template." Click YES.
On your WORD screen, go to FORMAT, then DOCUMENT.
Once on DOCUMENT, click on MARGINS and you'll be able to fill in the settings for your margins.
If you want more specific directions along with screenshots to guide you as you go, check out About.com's margin changin' tutorial.