Iris Dark is a flat theme that uses varying shades and tones to create distinction and a modern experience. It supports Gtk 3.10, Gtk 2 (using the Murrine engine) as well as Granite Widgets.
The icons are not released yet, and the shell theme is Elegance Colors: fav.me/d525x6c
If you wish to, you can donate some money to help support the development of the theme.
Happy tweaking License: GPL 3.0
EDIT: I want to say thanks to everyone who's favourited, downloaded or even viewed the theme! I never expected it to get so much attention from everyone! Thanks guys
Double EDIT: Daily Deviation!! Wow! Thanks again everyone!
2014.02.17: Tweaks and experimental Unity CSD support for Ubuntu 14.04
2014.02.02: Fixed bugs with Firefox and tweaked Terminal.