By default, the Firefox address bar is set to perform an "I'm feeling lucky" Google search. Here is what you need to do if you want to change the default behavior to perform a regular Google search instead.

• Type about:config into the address bar.
• In the filter bar, type keyword
• Double-click keyword.URL and change to http://www.google.com/search?btnG=Google+Search&q=

Another way to accomplish the same thing is by adding the following to the user.js file.

// Change to normal Google search:
user_pref("keyword.URL", "http://www.google.com/search?btnG=Google+Search&q=");