But if you'd prefer a bit of a "dark" colors... then Atolm-gtk3 might get you interested. This theme actually is based on the GTK2 theme called Atolm which also looks pretty good.
When you install Atolm-gtk3 you'll get ...
*. A toolbar of its own, Buttons.
*. Added gradients.
*. Combo boxes and padding.
First download the content from here and extract it. Then copy that folder into "./themes" in your Home folder. This is another theme from Deviantart... thank you TheDeviantMars for this cool looking theme. Enjoy.