I've been a dog owner all my life, and I've never had a serious issue with a dog attacking me, but to make blanket statements about how to handle dogs is like making blanket statements about how to handle people. Most people, and dogs, probably 99.9% do not actually mean you any harm. The dogs just want to chase you, and wouldn't know what to if they caught you. However, there is that tiny .01%, be they people or dogs, that DO mean you harm.
This is an incident I recall from a couple years ago, not a cyclist, but the classic mailman vs dog. Read the article. This mail carrier was 6 foot 3", 300 lbs, and he thought he was going to die. If he cannot pull off the Alpha male routine, you're not going to either.
http://www.startribune.com/local/min.../99473224.html
Pit bulls are unbelievably strong. Pound for pound, pit bulls are much stronger than labs or shepherds. And dogs in packs can behave much differently than a single dog ever would.