Since the initial concept was obvious and simple, I didn't  want to use the "computery" or plastic apperance that is so frequently used for this kind of subject. I went towards craftsmanship and tangibility.  
Here are two main materials selected for the overall feel:
Textured paper with soft edges giving a cotton-like apperance.
Brushed aluminium with subtle surface details.
Color palette is based on a "official" HTML5 color.
Paper was renderd in subdivided state to keep it smooth and organic.
512 x 512
128 x 128
64 x 64
16 x 16
This tiny version keeps the recognisable features well visible :)
Looks good on a bright background aswell.
Of course there must also be a flat design alternative!
Both versions side by side.