This is a tough one! I think you need to be really good looking to look good blonde. I kind of prefer brunettes but in the case above I would say having a beautiful face wins as you can always work on shaping up the body!
if you fancy both or them.............. choose one of them by there personality, goodness me. who do u get on with better. who could you see spending your life with, who would you like ur family to meet. It really isnt down to what colour hair she has! and if your not looking for something serious and just fun then does it matter?
It actually depends.. If you have lights eyes go for the darker color; it will bring the out the color in your eyes. If if you have dark eyes, go for the lighter color. :)