Ever since Google started prioritizing Google+ in search results, I've been courting new search engines. I tried Bing, which was fine, but the aesthetics of it really weren't pleasing to me. More recently I've been using Duck Duck Go, and I like it pretty well. It has a more minimal look that I prefer, and the search results have so far been pretty good. I can access Duck Duck Go easily from within Alfred1, but I also use the search box in Safari a lot, which only has options for Google, Yahoo! and Bing. The suggestion I heard the most was to edit your hosts file in order to replace Yahoo! with Duck Duck Go, but that wasn't super appealing to me.
The solution I liked a lot more was to install an app called Glims, which adds all sorts of functionality to your search bar as well as add other search engines. I'm running the latest version of Safari and it works great. I actually found out about it on Duck Duck Go's Safari support page, so I was surprised I hadn't seen it mentioned elsewhere.
I made my Alfred shortcut ddg since it's easier to type than duck. ↩