I've had my fair share of dog problems. I try SIT!, I've tried growling at them, putting my rucksack in between them and me as a shield (was effective!) I've done the occasional kick, I've poked a couple of times with my hiking sticks and last year I even punched one on the nose! More of a panic on my part but it worked. One bloke I met on the Pennine Way even suggested I should try weeing on them. Never had the nerve to try that! A couple of years ago I met a bloke in the Lakes who had bought a lazer pen to try to disperse cows, told me he hadn't tried it on dogs, again never tried that, seems a bit high tech to me?
My primary gripe is with owners, I've rarely met an unnacompanied dog. Why do some owners think their dogs speak English, I've seen no evidence of it. I really hate it when they shout from 200yds back "Its allright he/she won't hurt you" One owner shouted that to me when her dog, a red setter jumped up and gripped my wrist between his teeth. I kneed him in the chest and he let go, the lady then blamed me! I just walked off and ignored her.
I had a situation in Kent a couple of years ago. I was on the footpath, this blokes fence backed onto the field I was crossing, he let loose 5 small dogs who charged at me and tried to nip at my ankles. When I shouted out a protest he just went back into his garden and left me to it. When I finally got over the stile onto the road I was furious and marched up to his front door and banged the door with my hiking stick handle. He never answered! I complained to Ashford Council but they did nothing, one of their pals no doubt?
I agree with Doddy, those French sheep dogs can be really scary, I've only met one at a time, five would really freak me out!