"I've owned dogs for 10 years now and I think a loud bark and a beware of dog sign are the best theft deterents money can buy. Why mess with a house with a dog, when the one next door has no dog."

+1. I have a big stray lab mix. I found him playing in the street. No one wanted him or would claim him. I kept him, and don't regret it. 90 Lean pounds, all bark. Boy, folks are scared of him... but he's a big softie. Still a great break-in deterent. Never had a thing stolen, no break ins.