I just orderd the don sullivan training dvds and such I don't have it yet but I 3dogs and 1 of my dogs when we first got him he was a holly terror. He was agressive towards everything and sometimes even the family like my parents and even me he bit me once and my mom told me if he does it again that we would have to put him down and guess what he bit me again and I had beg my parents not to put him down that he shouldn't be uthenized.
About a month ago i watched this show called the dog whisperer with Cesar Millan that is when I reallized that it our faults for our dogs misbehavior that we didn't become the pack leader so our dogs took that role back then. And what made it worse was that we didn't have that calm and assertive energy it was more nurvis and worried energy. So I started using Ceaser's meatheds like stay calm and assertive set the rules, bouderies and limitations and have exersize, disapline and affection in that order and much more and I can't wait to get that Don Sullivan training thing and use everything that I learn to make our dogs form unstable to become a stable pack.
Oh and one thing to people who are training their dogs it's all about the energy you use don't be tense just stay calm & Assertive cause that's what dog's feed off of not what you say to them. Also gain trust and respect form your dog that will also make it a bit easier to train and soon enough you will become the pack leader.