I honestly don't think you have much chance if a pack of dogs decides to attack you. The damage of one trained dog can be devastating. And military trainers will tell you that you can empty a clip into a trained dog and it still won't let go. Yes, it will die eventually, but I certainly wouldn't want to imagine what shape you'd be in (or in how many pieces).

I don't even want to think about a pack of feral dogs. The trick is getting them not to attack you in the first place. And that's quite the trick. Pepper spray has been suggested, but it's also been noted to provoke attacks (at least with bears).

My strategy would be to avoid dog packs at all costs. Once they mean business, you arms will quickly become useless. I'd slowly walk away, avoiding eye contact, and find a safe perch. Of the many tactics discussed here, one that's been omitted as far as I can tell is punching a dog as hard as you can in the nose. That's what my trainer told me to do to establish dominance over a very alpha dog the first (and only) time she snapped at me. (However, do this at your own risk.)

Wow, this is one morbid thread, as someone mentioned above...