After my home was broken into twice, first I got an alarm system, next I got a gun, then I got a doberman.
And I can say with all honestly that I feel 100 times safer with a dog than with the alarm and gun.
In other words, I fully support the idea of having a dog.

As far as breeds, I obviously support getting a doberman. We also have a Shih Tzu/Maltese mix. And even though the doberman weights 10x's as much, they play great together (in fact, its usually the Shih Tzu that chases the doberman around our yard).

The only two cons is that they shed a good bit and need a lot of exercise.

Akita. Depending on the breed some are of a Japanese police dog decent and have inherent guard dog instincts. They are very loyal and good with kids & elderly. Sometimes there'll be more fiesty ones or more spunky ones or various personalities, as with most every breed but they are considered a well known reliable dog that will protect you and your's for life.

Growing up through jr. high and hs we had 2 completely different Akitas, one M one F. The M was of the bigger police dog breed, he was known to corner people who were suspicious and/or kind of maneuver them where he had the complete control over there every move and then just wait for our command. We never taught him that, knew his mom and her family also..good dogs never trained to fight or even guard, they just did it instinctively. The F is of a different kind of Akita that is a bit smaller and stockier. She is not exactly the kind I think you are looking for but check into the Japanese police dog breed of Akita.

A famous scenario is that of the OJ Simpson case which gets any Akita breeder or friend there of to question the outcome of that whole deal. Akitas of the Japanese decent are well known to be loyal and caring to their people who home them, they almost (well do) carry a sixth sense about them and can weed out the good from the bad. For someone with malintent to get by without there notice is beyond anything usually heard of the breed.

Also, the Akita is fairly quiet, listens and is good with activity. Their variety in color is also remarkable but honestly I have always felt the dog chooses you just as much as you choose him or her, and the path just kinda unites so don' stress too hard

Dobermans are by far a superior dog. Closely followed by the boxer. I say this because I have owned both recently. They both have passed away at ripe old ages.

The only drawback to the dobie is that they arent all weather dogs. Neither is the boxer for that matter.

Loki, my doberman was a beast of a dog 97lbs of sleek graceful muscle. He was shutzhund trained when I lived in Germany. One thing to note that someone mentioned earlier is the breeding in the USA compared to Europe. They breed their Dobies smaller and stockier there. They are short and muscular with little refinement. Here ours are a little taller and leaner and a little more graceful. One thing to remember is that the doberman breed is still rather young for the most part in europe...yes they came from there but many of the good ones were shipped out of europe during world war II. Most of what was left in Germany died during the war because they strapped explosives to them and blew things up with the dog.

here is a blury pic of my two...one is a golden who is getting old and the other is a chow mix who is middle age