By default, when you type something into the address bar in Firefox it will use Google's "I'm feeling lucky" search to send you to the 'best' website. I never use this feature and (more importantly for me) my workplace blocks a certain parameter in this query so I wanted to change this behavior.
This is so easy to change it's almost trivial. Simply open the about:config page in Firefox and filter for "keyword.url". The one remaining preference will be the one you want to edit. Double click and replace the value with:
http://www.google.com/search?q=
This will cause Firefox to perform a nice vanilla Google search.