Ambiance DS BlueBLK is a nice dark Unity & Gnome Shell theme. The theme is originated from the Ambiance DS Blue theme, but with a few color and graphics modifications. In this tutorial we will help you install it under Ubuntu 11.10/12.04. Here is a screenshot of it Under Ubuntu Oneiric (Unity):
Ambiance DS BlueBLK Installation
There is no PPA for this theme, you can install and enable it manually with the following commands from the terminal:
wget -O Ambiance-DS-BlueBLK.tar.gz http://goo.gl/qjWw0
sudo tar -xzvf Ambiance-DS-BlueBLK.tar.gz -C /usr/share/themes
gsettings set org.gnome.desktop.interface gtk-theme 'Ambiance DS BlueBLK'
gconftool-2 --set --type string /apps/metacity/general/theme 'Ambiance DS BlueBLK'
If you want to use an icon theme under Ubuntu, you can choose one from here.