1.) This has nothing to do with buying a particular "breed". A dog in general can get alot of attention, and attention increases their chances of getting caught, thus deterring them from B&E.
2.) I don't give a fuck if my dog bites someone if I'm not around...wanna know why? B/c he's locked in the house when I'm gone. That being said, strangers shouldn't be in my house when I'm at work, catch my drift? If I'm with him and he can see that I'm comfortable, he doesn't mind anybody, he wags his tail and wants to play. If I'm asleep and something startles him or someone bangs on the door at midnight he goes ballistic. This is how I like my dog...kinda the reason I got him. I can leave my fiancee at home by herself and feel confident that he will deter people from even knocking on our door. What good is a dog (for home defense purposes) if it won't at least growl or make you think he may bite??
My dog is the kindest dog in the world and has never bit anybody and I hope he never has to... But I know if someone truly tried to break down our door or break thru a window, he would at a minimum make ferocious barking and growling that would alert the neighbors of something fishy going on.