Allow me to participate, guys. I wanted to keep it as simple and legible as possible.

A few details:

• Two tones of green, that emphasize the "eco-friendly" idea.
• The interior design tries to simulate the veins of a leaf.
• Circular shape, that refers you to both "coin" and "planet" concepts.
• It happened casually, but if you really search for details, the veins form a V of victory, like in wrist watches advertisings.

I add three variants, without shadows, parallel shadow and area shadow.

http://i.imgur.com/N8jlSXE.png

(I don't know how to show a preview here, nor if I can do it with my current rank)