[J.B. Hickok]

Why not a mutt? There is nothing that says a collie/sheperd cross would not excell in the role you are seeking. It is a common cross/mix breed and not too terribly difficult to locate.

I agree with much of what has been said and disagree with other comments. But the bottom line when dealing with any breed of dog is there are no NEVERS, ALWAYS, BEST or WORSE.

Pick a puppy you both agree on and love. Do three things in its initial training:

Do not let anyone other than the people living the house touch it when it is young. (Puppies are cute and people love to show them off and others love to pet them and going on about how sweat they are. By taking the pup out and letting everyone and their grandmother pet and love on it you have just taught it that everyone in the world is its friend. It should distrust everyone other than you and the wife initially. Once it has learned to distrust people there will be time to teach it that grandma, who comes over to visit on weekends, is acceptable and should not be eaten alive. It is up to you how you train it to react to your mother-in-law.)

All puppies will playfully "react" when they hear a stange noise. Encourage this. Tease them. Drive them nuts with this. There will be time later to sort out with them what is acceptable to bark/growl at and what is just wanting to hear their own head rattle.

Love it.....a lot. If you show the puppy love it will return it ten fold. That love will also be returned in the form of wishing to protect you and your wife, the ones that show it love.

Do these three things and train it in basic obedience in its first six months and then plan any type of formal training that seems needed and justified in terms of applying money where it is not wasted.

(As a side note; Do not try to compare police dogs with one to be used for a family pet/protection. They have two completely different functions.)