Last summer, when I had my dog incident, I did the stop, put the bike between the dog and I thing, and yelled. I *think* I squirted it with my water bottle, but about then, the dog lost interest. When the same dog chased my husband about a month ago, he was going the opposite direction, in the same spot, and was going about 30 or more down a little hill. Nothing would have worked, but his outstanding bike handling skills, which did save him.
I am not sure if I could get the pepper spray or even my water bottle out quickly enough to use if I was actually still on the bike. But I have no qualms about using anything to protect myself. I honestly admit I don't like dogs under any circumstances, but in this case (and most) it's the stupidity of the owners that cause the problem. In my old town, there was a leash law and most people had invisible fences. Here, even the owners think they "own" the road, walking 2-4 abreast and not getting over into single file when a bike or runner is approaching, with warning. More than once I have let loose a string of expletives when these women look at me like I am the one who is crazy when they don't move or call their dog.