I have a Samoyed that I show. It is without a doubt the most absolutely perfect breed I've ever encountered. It's not a "small" dog (mine is about 65 pounds), but there's absolutely nothing scary looking about it. They look like little polar bears and have the famous "Sammy smile" that always makes it look like they're happy and thusly...not mean.
The only downsides to them are that they shed quite a bit (Siberian reindeer herding dogs...they needs their fur) and that they're one of the more pricey breeds out there--sort of a get what you pay for sort of deal.
Other good ones for kids are standard schnauzers (amazing with children, fiercely loyal, but again--expensive), Greater Swiss Mountain Dogs (though these are large dogs...and probably the most expensive breed out there), Eskimos, and if you get it at a really young age so that it'll bond with you and the kid--though this is a very, VERY large dog--a Great Pyrenees. But these are more for if you want to be able to send your kid out alone in a ghetto at night and not worry about him getting hurt cause the dog will kick the crap out of anyone that even looks at his "charge" (it's a shepherd dog) funny.