A tall order you give us 
You need a Guard dog, not a thieve licker or a signal giving barker. ( Labradors, and all like breeds are out )
You need a "person / family " guard dog, so all the big "outside dogs", property gardians, are out ( sheppards, mastiffs, pack breeds, Catahoulas, etc, etc, are out )
Having small children and a wife ( who is not too keen on "agressive famed" breeds as I understand your issue ) you do not want overtly Alpha breeds ( because they will only respect you, as the pack leader ). Although, with small exceptions this is perfectly correctible and this is what I would want in your position.
I would center my choices on dogs with inbred family protection sense and with "leiterfuhrigkeit" ( conductibility ) ie, dogs that like to be led and live with, people.
German Sheppard comes foremost ( not my dog breed in any case ). Rottweiler, irrespective of what your wife fears, comes a close second, as come the Giant Schnauzer, the already mentioned Airedale, as several ohers ( Boxer is too playfull for me, but would fullfill the order )
Last but not least, and the most important, considering the environment you live in, carefully choose the dog, check the breeders, speak with them. You will want to avoid a puppy mill or a mall center lfs dog at any cost.
You need a Guard dog, not a thieve licker or a signal giving barker. ( Labradors, and all like breeds are out )
You need a "person / family " guard dog, so all the big "outside dogs", property gardians, are out ( sheppards, mastiffs, pack breeds, Catahoulas, etc, etc, are out )
Having small children and a wife ( who is not too keen on "agressive famed" breeds as I understand your issue ) you do not want overtly Alpha breeds ( because they will only respect you, as the pack leader ). Although, with small exceptions this is perfectly correctible and this is what I would want in your position.
I would center my choices on dogs with inbred family protection sense and with "leiterfuhrigkeit" ( conductibility ) ie, dogs that like to be led and live with, people.
German Sheppard comes foremost ( not my dog breed in any case ). Rottweiler, irrespective of what your wife fears, comes a close second, as come the Giant Schnauzer, the already mentioned Airedale, as several ohers ( Boxer is too playfull for me, but would fullfill the order )
Last but not least, and the most important, considering the environment you live in, carefully choose the dog, check the breeders, speak with them. You will want to avoid a puppy mill or a mall center lfs dog at any cost.
