I totally agree on the comments about any dog can be protective. Our old golden retriever was as gentle as their reputation is, never an issue with anyone or anything. Happy for the meter reader to even come, she'd greet him no problems. Not a guard dog in any sense. But one day mum had someone come to the door acting in a manner that had her afraid and our dog stood beside mum, teeth bared, snarling and hair standing up. It was not her nature to do this, she was not trained to do this but she felt that there was a need to protect.

Our beagle barks only when there is an issue. She doesn't bark when a car arrives or people turn up unexpectedly. She carried on a treat though when there were people walking along the otherside of the fence when it was the middle of a work day and she knew that normally nobody would be there. Our c ocker spaniel also acts to guard, she even tried to bail my brother up when he came into the backyard and we weren't home. He was there to feed her when we were in hospital having DD1 but although he was somewhat familiar to her, it was totally unusual and in her world, totally wrong. She wouldn't eat the food he left for her either.

I don't know what sort of circumstances you're going to be living in where you feel you need a guard dog but maybe these stories of non-guard breeds might help you make a decision.