Heh, that's more than I could say for our Lab. He'll bark, but he's never shown ANY intention of defending us, even when every hair on Shiner's body would stand on end, Buster would just wag his tail...
Ripley is always too busy growling at strangers to care WHAT they're doing to me, LOL.
That's the main reason I want a Doberman or a GSD. Both are very obedient, watchful, serious dogs that like to keep an eye on their mischevious humans.