So, with an AMOLED screen, colors are generated by illuminating individual LED's. Black is 'created' by NOT illuminating LEDs. Needless to say, dark screen = less power (unfortunately black is not zero, but its as close as we can get). As a result, some of the more serious battery power conservationists out there run black or very dark wallpapers to minimize power usage. I just thought I'd share a handful of my favorites. I didn't make them, I just like them!
All Black - The name says it all.
Blocks - What would you call it?
Black Steel
Carbon Fiber
Carbon Fiber 2