Wow, this conversation has been ongoing for many years.  Things have changed dramatically for me.  I have had two more Fila's since then.  Both Mexican Imports.  One of them was dysplatic by 6mos old.  The next is a little over a year and has great hips and Zero temperament, with ZERO socialization.  I disagree with the theory that no socialization creates a better guard dog.  The best "guard dog" I have now, is a 6yr old Cane Corso that has been socialized immensely.  He loves people as long as he knows I'm  aware that they're there.  If I'm approached from behind or someone rings the doorbell, he becomes a totally different animal.  A stable dog defends because you are suspicious or afraid, not because they are.  In the past, I didn't believe that.  The proof of that theory is in my yard.  I now have 12 Cane Corso, 5 of them are Italian Imports.  The other 7 are American bred, by me or by someone else.  I also have the zero temp Fila.  Like I said before, true guardianship comes from the dog having the confidence to believe he can win, if the fight ever arises.  The Fila I had many years ago was a rare creature and I've come to believe it's not there anymore.  I will admit, I'd love to have another like him, but I don't think that's possible anymore.  He was very socialized by the way,  it just didn't matter.  He hated strangers regardless of whether he'd met them or not.  If they didn't live here, he would attack them, period.  For now, I'm very comfortable with the Cane Corsi that I have and their ability to defend.  They've proven they won't run, on more than one occasion.  I have though, socialized them immensely and the biggest difference is my personal protection doesn't wait in the car for me anymore.  It's right by my side.  JMHO, Jen