We have a yorkie and she is a lovely little dog, fabulous with children, cats and really every living thing. She's never been aggressive (lets the cat share her food) and has many boy friends as we are on a main dog-walking path, and has never had another dog attack her.
She's now 15 but in her younger days would actively seek out the children to play with, and was always waiting in the yard when we got back from school to greet them.
The downsides: very scruffy, mainly because we live on a farm, so we now get her hair cut two or three times a year (think Hairy McClary); not very trainable, but because she's little it's never been a problem, and I don't think we tried very hard (when we go for a walk she never leaves our side, so doesn't need a lead); likes the sofa and always pulls down a comfy cushion to sit on, not too keen to move when asked, but would never growl or snap; utterly daft with livestock, has never sussed that a cow or horse might kick, so walks around back legs with impunity - even worse now she's nearly blind.
She's been in robust health up untill the past few months when she started with bronchitis , and so is now on steroids, but until then had only been to the vet's once in her life.
She only yaps to be let in or out, never at other times, but she is quite persistent till she gets her own way.
She really was the perfect dog to have with small children.