What breed of dog is a good family dog / protection dog? ?

We are looking for the same kind of dog. We've decided that mastiffs are pretty much like pit bulls - very dangerous. Labs love everybody and will make lousy watch/protection dogs. Shepard is a good choice. We are also considering Japanese or American Akita, Rottweiler and Bernese Mountain Dog but for these I'm having trouble finding available litters in my vicinity.