This is the logo for the World Wildlife Fund. I think it uses positive and negative space very well. Both the black and the white space come together to create this image of a panda bear, an endangered animal that the WWF fights to protect. The Giant Panda logo originated in 1958, 3 years before the organization was founded. The goal had been to create a symbol that would overcome language barriers and be recognizable to all. The original logo was designed by Sir Peter Scott, although the current logo we all know very well was actually created much later after the organization officially changed its name to the World Wildlife Fund for Nature.

wwf-logo http://www.worldwildlife.org