Edit: you could also add this to Alfred. Alfred supports custom searches ( http://blog.alfredapp.com/2011/04/14/alfred-productivity-tip...) so you can just use http://www.duckduckgoog.com?q=SEARCH as the custom URL and replace SEARCH with the token that Alfred expects
But you bring up a good point -- DuckDuckGoog is still useful with Alfred since it saves you from having to manually create a bunch of custom searches.
Edit: you could also add this to Alfred. Alfred supports custom searches ( http://blog.alfredapp.com/2011/04/14/alfred-productivity-tip...) so you can just use http://www.duckduckgoog.com?q=SEARCH as the custom URL and replace SEARCH with the token that Alfred expects