Originally Posted by xstokerx
black pixels are off using less battery white pixels are on using more battery I cant see themes using more battery unless they are bright colored.
This is only true for AMOLED type screens. On LCD screens (which the One X is) the pixels are lit no matter what color (including black) is being displayed. What color is displayed is solely determined by how the light is filtered through the polarization film. But the light source itself (backlight) is always full white.
To get back to the OPs questions, the skin is just different backgrounds and colors, none of which should have any significant effect on battery life. I've never noticed even live wallpapers to effect battery life all that much, either. The exception might be a 3rd party skin or LWP, that is very poorly coded. But in my experience with custom skins, I've never noticed any significant difference in battery drain.