How to disable auto preview for *.doc *.docx in finder?
Open Finder, press &#x2318;+G and enter /System/Library/QuickLook/ to go to the QuickLook plugins folder. Click on Office.qlgenerator, press &#x2318;+I and rename the file to Office.qlgenerator.backup. Now, press &#x2318;+&#x2325;+esc and relaunch Finder. If ever you want to turn the plugin back on, simply remove the .backup from the file name.

Essentially, plugins tell QuickLook how to render a preview of a given file type. Without the Office plugin, QuickLook will by default show only the icon and information about the file (i.e. size, date created, etc.)

Note I'm pretty sure this removes QuickLook's capabilities of previewing OpenOffice files as well.