Hi.
I have, well my 7DD has a rottie/husky mix, so he is a big boy. Just the appearance of a large dog even though the dog may just be a big "give me love dog", is sometimes a deterrant. He doesn't act aggressive, isn't really a barky dog, but I know if someone tried to harm my DD, that would be it for the guy. They are a month apart. It is DD, DM and myself, so if someone comes to the door, they just see a big dog come to the door and ask that I don't let him out.
My dog previous to Nikita, was a husky/shepard mix and she was very protective, very vocal. She was the smartest dog I have had. She would bark if the phone rang.Once, during summer time, I just had the screen door closed and she saw our neighbor fall across the street and the lady was calling for help and Brina had a Lassie moment and got my DM's attention enough for her to hear the woman call for help. When I had my DD, my dog was 13 and we didn't need a baby monitor, my dog would sleep under her crib, by her playpen,etc. People came to see my DD, Brina would let them hold her, but she would follow them if they walked around with DD.Before my DD came along, I would take Brina for car rides and we would stop at 7-11 and she would sit in the car and if anyone came near the car she would just go crazy. Sadly a couple months after DD was born, Brina was dianosed with cancer and we had to put her down.
My first dog was a sheltie mix, she was just too lovable. She even let a burglar come into our house, but it was always belived that whoever it was knew her.
My ex-husband is thinking about giving DD and myself another dog, it will be another german shepard. I totally agree with the previous poster about training. Also, dogs are pack animals and they need to know who the alpha dog is. My next door neighbor has a doberman and a mini doberman, and the mini is more protective than the big doberman. A couple years ago, Hurricane Isabel rearranged part of my house and our shared section of fence was torn down and we had to put our dogs on leads because the workers had to remove the tree and work on the house,etc. they were not crazy about 2 big "guard" dogs and one fiesty min pin near where they were.
Even if the dog you get isn't "a barky or growly type dog' just the size and if someone asks if they will bite, say yes. More than likely they aren't going to want to find out if the dog really bites or not.
Good luck with whatever breed you decide.