Below is my March desktop which resembles the older OSX Tiger look and a collection of favorite Gnome GTK3 themes. It is nice to have these all in one place.
The above theme is GrayDay theme and can be downloaded here:
http://gnome-look.org/content/show.php/GrayDay?content=149310
To install the Elements-GS Gnome 3.x theme:
sudo add-apt-repository ppa:webupd8team/themes
sudo apt-get update
sudo apt-get install elements-gs-theme
Source: http://www.webupd8.org/2011/10/4-beautiful-gnome-32-compatible-gtk.html
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You can add the Elementary and Evolve PPA repositories below:
Then just search for Evolve theme from the Synaptic package manager.
sudo add-apt-repository ppa:webupd8team/themes
sudo apt-get update
sudo apt-get install evolve-gtk-theme
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To get the updated Ambiance and Radiance light themes
type the following on a terminal:
sudo add-apt-repository ppa:victored/light-themes-evolved
sudo apt-get update
sudo apt-get dist-upgrade
You can also go into Synaptic and search for "light themes" to avoid upgrading everything.
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Remove overlay toolbars, from root terminal:
sudo apt-get remove overlay-scrollbar liboverlay-scrollbar3-0.2-0 liboverlay-scrollbar-0.2-0