nah get a pit! who needs a house alarm when i got a 80 pound monster running around lol

Not allowed in Aus to have pits.
Beside Blue Cattle dogs are more than enough. They can bring down a Kangaroo Buck and that is no mean feat. Trust me you don't want a pissed of Bluey near you. They don't have that mad presence and size but they are extremely fast, very big on wounding over killing and can be just bad tempered. They also very loyal, good working dogs and soaks to their family.

Funny story. Neighbour where I grew up used to breed Red Kelpies. Kelpies being a popular working dog where I grew up. The local Parks and Wildlife Ranger (so yes this is a story from 20 years ago) had two Pig dogs. Ridge backs with quite a number of big and nasty breads crossed into them. One day they got out and came up to my Neighbours place and threatened my neighbours. Their Male Kelpie jumped the 6 foot fence gutted one of the pig dogs and badly savaged the other.
Kelpies are usually quite a a nice tempered working dog weighing roughly 40ish pounds about the size of the blue cattle dog in the pictures above. Easy to train, love working, hyper active if they don't work. Very loyal and you can safely leave your kids in the back yard with them, even if you kids are not gentle with animals.  Someone else's kids are fine as long as they don't pick on your kids. Then there would be a problem. This one was around the 50 pound mark and the Pig dogs were some close to the 110 pound mark.
I think a working dog is great as a deterrent and the bonus is the criminal is still there when you get up/home so you can kick them a few times before having the cops come and take them away.

Oh yeah, I love those dogs. Had a Blue/Kelpie cross and a Red Cattle Dog too.

Fast. Damn fast. And they never seem to run out of energy. The red could vertical leap as high as my head. And when you played with him it was like playing "ole" with a bull how he'd charge and yeah good times.

Michael