Wow, I stirred up a hornet's nest here
I own 2 dogs, love em to death, would use deadly force to protect them in a heart beat if I had to. That said......
2 years ago, I was walking my mutts (both leashed) around the block near my parents house. They are small dogs, about 20 and 30 pounds respectively, and not aggressive towards other people or animals. While walking on a public street, an unrestrained german sheppard of good size did charge us.
Now I can't out run a charging GS, especially with 2 leashed dogs of my own. In a very quick moment, I picked out a spot about 20 feet in front of me, and decided if the GS hit that spot, I was going to engage. At about the 30 foot mark, I had my hand on the grip of my G26, and was about to start my draw cycle. At about 25 feet, the GS stops, snarls in a very hostile manner (this was not a "hello" bark, or "Stay away" bark, more like a "I'm gonna chew on your intestines" type bark), then turns around and just leaves.
When I got back to my parents house, I mentioned it to my dad. My dad wasn't the least bit surprised, saying he had gotten several complaints about that same dog (he's the head of the HOA). I told my dad he might want to warn the dog owner that his pet was 5 feet or less from being fed as many 147gr HST's as I can crank off before becoming fido bait.
As a dog owner, my 2 cents is: If you own a medium or large sized dog, and its the LEAST bit aggressive, either keep it leashed, chained, fence, whatever, or risk having it being taken out.