Pull The Safari Omnibar Switcheroo

"AnySearch" Safari Extension — Mac OS X Tips

Want to move on from Google as your search engine and replace it with DuckDuckGo (as so many seem to be doing)? For a while you would have to resort to hackery, but with this latest extension for Safari 6 and its omnibar you must hack no longer. Follow the link above and scroll down to the "AnySearch" extension. Download, configure, enjoy.