Eco is a new theme added to the Bisigi project. It is based on Shiki Colors and comes with a beautiful wallpaper, 2 GTK and Metacity themes (but only 1 available in the Bisigi PPA) and an icon pack.
To install all the Bisigi themes in Ubuntu, simply use the following PPA:
sudo add-apt-repository ppa:bisigi/ppa && sudo apt-get update
sudo apt-get install bisigi-themes
Or install just the new Eco theme:
sudo apt-get install eco-theme