Although a little late on the update as most of us will have to say goodbye to Gnome Shell 3.4 soon, Hope gtk3 theme was updated to be able to work on 3.4.
Hope is a very clean and nicely designed dark theme that looks modern and beautiful. Although most of its elements are blackish, it manages to contain optical succinctness on clickable elements like buttons etc.
To use this theme simply extract the downloaded file under /.themes and choose it from the “Advanced Settings” menu on the “Theme/GTK Theme” category. If that sounds too complicated, check our comprehensive guide on how to theme Gnome 3!