Summarize:

Dogs can be great family pets as well as great tools for protecting your property from intruders. Some dog breeds are better for property protection than others. With the proper training, quality guard dogs will bark, bite, intimidate, and chase intruders away. In general, the best dog breeds for protection include:  Bullmastiffs Doberman Pinschers Rottweilers German Shepherds Akitas Do not simply purchase the first dog you find. Dogs need to match the personality of their owners and you need to make sure you purchase a dog that you can take care of. For example, guard dogs are very active and need to be exercised often. In addition, they can be aggressive towards others if not properly trained; therefore, it is important you shop around until you find the right dog for you. Additionally, while it is always nice to adopt a dog from a shelter, these dogs often need extra training due to possible emotional and physical problems that arose before you owned them; therefore, it might be a good idea to purchase a puppy from a reputable breeder if you are purchasing a dog for home protection.
Research good guard animals. Shop around.