
I have a 16 month old GR who also suffers from visit the world syndrome. Not just dogs either, if I don't tether him to me when small children appear he'll want to go say hello to them as well. (and pensioners, workmen, shopkeepers, men, women, teenagers... :-D)
Things that have helped me:
1) As Jeangenie suggested, the more he plays with dogs the less obsessed he is with meeting them. Especially if they are more sedate adult dogs. Then mummy and her balls and throw toys starts looking pretty fun.
2) Long lines are heard to use in some places but if you have a playing field with lots of people and dogs nearby they make great practice areas. I call him 20-30 times. If he comes back he gets a fuss and a treat. If I have to reel him in like a speared fish he gets nowt but a nice pat on the head.
3) Valium and surgery to remove your embarrassment gene ;-) - because as hard as I try he slips one over on me now and then. But then whenever he does get to say hello to anyone, or any dog, it's with a waggy tail, great joy and complete non-aggression. And that makes me proud of him and love him all the more.