According to a 2008 research conducted by the universities of Pennsylvania and Taiwan it seems that our beloved akitas are the most aggressive towards other dogs.
It's although very interesting that the research doesn't mention any hierarchical social structures, leaders of the pack, dominance etc. On the contrary, they mention the purpose that each breed was bred for. This comes to no surprise for us, since humans have used dogs for thousands of years against other animals, dogs (in dog fighting) and even against other humans.