The police "Use of Force Continuum" is pretty much what I think of when it comes to how I should handle a dangerous person or animal. It goes something like this:

1. Physical/Verbal Presence (look and sound tough)
2. Light hand-to-hand techniques (blocking, arm locks, pushing ect)
3. Mace/Pepper Spray/other Less than Lethal
4. Heavy hand-to-hand (punches/kicks)
5. Baton
6. Threat of deadly force
7. Deadly force

It's not perfectly adapted; for example, as a citizen I avoid the hand-to-hand stuff whenever possible, instead preferring the methods that allow me to keep my distance and escape. But, the basic idea is there. If it came to aggressive dogs I would do the following:

1. Aggressive stance and yelling
-if that doesn't work-
2. Pepper Spray them and try to get away
-if that doesn't work-
3. Hit them hard with stick/baton/whatever
-if that doesn't work-
4. Shoot if armed and I feel it's necessary to keep them from attacking

With that said, if I see an aggressive dog latched on to a child's arm or something it's getting a kick to the head and a couple rounds of hot lead. There's no reason to waste time at that point.