I don't know if the OP is still reading our replies but here goes as far as my opinion with regards what is s good dog to protect your home.
Mastif. (Neopolitan, Bordeaux, English, Majorcan (rare breed) are perfect.
Dogo de Argentina
Whilst my Dobe barks at folk I got him to protect me and mine as well as deter folk from thinking about entering my home.
By the way I had a Mastif (Majorcan) who once bit off half of someones foot (literally) as they tried to climb over the fence. However, saying that, if the intruders know there is a dog and they want into your house they will likely dispatch the dog first.
To anyone that knows the breed, pit bulls are TERRIBLE guard dogs. Absolutely USELESS against any thief that knows the breed.
People steal "guard" pit bulls out of yards all the time. Walk right up and take them off their chain and walk out with them. They are NOT territorial, they will bark along a fence line but most times, if you call their bluff and go in, the worst you'll get is knocked over and slobbered to death. Then they'll show you to the vault, show you the pass code and hop in the truck to make the get away with you.
They were NEVER intended to be used as guard dogs. They lack a territorial / possessive nature. They have no attachment to territory or property, only their family.
They will protect their family to the death, but their family's home and property? Not so much.
Boxers are also not very good guard dogs. Again, good potential family protectors, but not good property protectors.
Too many people assume that just because a breed is known to protect PEOPLE, that it somehow extends to PROPERTY as well. It does not. A Protection Dog and a Guard dog are two different things.
A Doberman, like the boxer and pit bull, makes a good PROTECTION dog... But leaves quite a bit to be desired as a GUARD dog.
Geese, however, AWESOME! And if socialized they can be great with company once the owner makes it clear its ok. When we lived in England, we had some geese and they wouldn't let people out of their vehicles unless we came out to greet them. Once we came out, the geese would leave them be. They would tap on the door every morning for bread and scraps too. LOVE THEM! When we have property, I'm going to have a nice big gaggle of geese.
ETA: Other interesting "Guard dogs": Alpaca, Llama and Emu. Emu scare the crap out of me, I was chased by one as a kid (totally deserved it), and they mean BUSINESS (and can kill you). Alpaca and Llama are nothing to scoff at too, they're sometimes used as protectors of other livestock against small predators. Not many thieves would know how to respond to getting charged by an emu or alpaca. XD
Game-stock roosters... The down side is these guys will go after you just as soon as going after a stranger.