I agree with waruikazi that bull terriers make great protector dogs and family dogs but unfortunately due to the shape of there skull the average person does not appreciate there look, and when they run in to your legs with there head you know it usually with a bruise but this breed was never suggested by myself earlier as he wanted a large breed and they come more under the small to medium statue. but they will defend your property and yet are great with people and kids and now you can get miniature bull terriers which are nice looking dogs . i personally have only met one mini bully in the flesh but nice little dog.
i truly think if you want a large dog , easy to maintain , trainable and biddable, good for house protection, but not overly aggressive and , good around people/family and something you may comfortably be able to control and handle ( with training as any large breed does require training / as does small) ................. i think you may want a rhodesian ridgeback
but at the end of the day what do you really want this dog for ?????
a mate, a companion,, a friend,, a protector,,,loyal,,,,,, this will describe any dog you choose pure or cross
or an agressor ,,, able to attack,,,, guard your property with its life,,,,,, then you are looking for a few selected breeds and a future lawsuit...................................
just get the the dog that appeals to your likings as it will be with you for at least 10 plus years if you are lucky
most dogs will naturally defend there owners/family and property without having to be an agrressive dog but i am assuming you are wanting a breed that has that audacious persona to prevent someone thinking twice of coming in to your yard even though your dog may just lick them i understand that ,but if you want it to train to attack i suggest you train a miniature poodle they are very excellent alert dogs and no one would expect it coming as your killing machine lolol