I do not know your requirement, living condition, where you would keep the dog? How much time you have to take care of it? How much money you can invest to buy then to maintain it? However I will give you a pep answer.
Doberman: A one man dog, it will not harm you unless you do anything hurting to it, while hungry don't try to remove its food, for surely ti will bite you, it will not allow any one to come to your house easlily, you can tame your dog to be ferocious or a bit friendly, cost of buying and maintenance is affordable.
GSD: A sensitive dog, a good learner, can smell things and identify, catches infections easlily and needs care. Not advisable to give an unhealthy environment, a good watch dog and a companion, cost of buying and mainteance is a bit expensive.
Labrador: A homely dog that you can have in your lap, this dog is a good listener and will expect you to teach and tame him. He is not good as a watch dog as a doberman and definetely will bark, it will not harm anyone, unless under extreme conditions. He is freindly with you and your household, cost of buying and maintenance is affordable. A perfect dog for the one who hasn't had any dog before.
Golden Retreiver: you can mix the the points that I have you for GSD and Lab that is the GRVR, but cost of buying and maintenance is bit expensive.
Hope this helps you.
My own experience