What breed of dog should i get.?

i am looking to get a dog. my house was recently broken into and i want a breed that is kind of menacing looking to keep strangers away but will be a good companion as well. i plan on setting up an invisible fence and a doggy door for it. the only problem is that i live alone and work during the dayso i wont be there to play with it during the day. i was thinking of a gernam sheperd, rottweiler, or doberman. i heard that sheperds will bark all day if left alone though,,and i do have neghbors.