title: Choosing between std::map and std::unordered_map
body: <p>Now that <code>std</code> has a real hash map in <code>unordered_map</code>, why (or when) would I still want to use the good old <code>map</code> over <code>unordered_map</code> on systems where it actually exists? Are there any obvious situations that I cannot immediately see?</p>