I'm basing my opinion on the experience we have had (me growing up and in my adult life).
I think retrievers, golden or labs, are wonderful companions for children. I will say that my usual Honey is good with two or three, but I do not trust her in large groups of kids. I agree with whoever said that having the puppy grow up with the kids is a good idea.
Other breeds that I have been exposed to that were wonderful with kids are: Cocker Spaniels, English Bulldogs, and Mixed breeds (lab/retriever mixes especially). I'm sure there are more, just can't think of them right now.
As you can tell, I like big dogs. But one day, I will have me a nice lap dog too. One day........