http://lifehacker.com/5216694/google-fx-adds-loads-of-features-to-google-search

The added features include related searches, Wikipedia results, thumbnail previews, Google suggestions, image lightbox, auto-paging, additional search engines, and more, but it's the integrated settings dialog that really makes this extension interestingyou can use the user script commands menu under the Greasemonkey icon to pull up the Google Fx settings, and turn features on or off to suit your own preferences.