Halti..

[Longcoat]

Definately worth seeing a trainer.

I have some friends with dogs that pull like crazy and they all swear by the sporn harness. Apparently its brilliant for dogs that pull. I've not used one, but one of the dogs is large and slightly nuts and it makes a world of difference for him

Lets not forget that the purpose of a training device is to teach the dog to learn and behave, not to manage the problem.

[Prydenjoy]

I'd suggest an easy walk coupled with lots of training. Berri used to be highly reactive and pull and lunge at other dogs (he's small, but the problem was still the same). I started at a distance, giving lots and lots of rapid fire rewards when we were in sight of something he would have lunged at. Gradually we could get closer and closer, now he's so much better, if he slips I simply say "watch me" and he gazes into my eyes and ignores whatever it is that would have set him off. Worked a treat, with the help of the easy walk you could manage the strength of your dog in case he slipped, but primarily focus on lots of positive training and you'll get there