I'm not a dog owner yet, but when I am it will be a German Shepard. I want something that is highly trainable, and German Shepards have a well earned reputation as being such, with their obvious roles in law enforcement, etc. I want my dog to be a guard dog when and where I train him to, be friendly when, where and to whom, I train him to, be quiet and calm when and where I train him to, etc. I know all animals are unpredictable and have instincts, but I want as close to a dog/robot as I can get. If I could get a dog trained with like a verbal "on/off" switch for growling and barking at anything that moves, and the rest of the time be playful, but quiet, I would. I know, it's difficult and probably unrealistic. But a German Shepard, with the right training, especially from birth, seems like the best path to that end.