This OSXDaily article Disable “Reopen Windows When Logging Back In” in Mac OS X Lion Completely describes a method of doing this.
You may have noticed that when you log out or reboot Mac OS X Lion,
you get a dialog window with a checkbox next to “Reopen windows when
logging back in” that restores all of your currently open applications
and windows.
If you don’t like it and you’re tired of unchecking the box to no
longer reopen the windows, you can use a third party script to render
the feature useless. To clarify, what this does is disable the feature
completely on a constant basis, regardless of whether that checkbox to
preserve windows is checked or not, the windows will not restore.
Type the following command to download the script, place it in the appropriate location, make it executable, run it, then remove it:
curl http://goo.gl/Z4EFC -L -s -o ~/fixlogin.sh && md5 -q ~/fixlogin.sh | xargs -I % mv ~/fixlogin.sh ~/%.sh && chmod +x ~/121dca51e66073624da420b6e1be61d9.sh && sudo ~/121dca51e66073624da420b6e1be61d9.sh ; rm ~/121dca51e66073624da420b6e1be61d9.sh
The content of the script is for those who want to know what's being executed and/or do it manually is:
#!/bin/bash
echo "#!/bin/bash" > /tmp/loginfix.sh
echo "rm /Users/*/Library/Preferences/ByHost/com.apple.loginwindow.*" >> /tmp/loginfix.sh
mv /tmp/loginfix.sh /usr/bin/loginfix.sh
chmod +x /usr/bin/loginfix.sh
defaults write com.apple.loginwindow LoginHook /usr/bin/loginfix.sh
Finally, if you want to go back to normal resume behaviour type:
sudo defaults delete com.apple.loginwindow LoginHook