I'd wanted to expand a little on the rescue dog thing. When you get a rescue dog, as soon as you adopt it they go right down to the pound and save a pound dog and bring it back to the rescue. So in essence you are saving two dogs. Check petfinder.com, and also you can just google rescue societies in your area. Sometimes you can even find rescue societies for specific breeds.
I strongly disagree that you won't be able to predict behavior and temperment. With pound dogs that may be true, but a rescue society is not an animal shelter. They are more like a boarding kennel. The animals are there long term. They are socialized and worked with. They have been under medical care. They are fostered out to families that might want pets but not long term commitment. The dog handlers get a feel of each individual dog's personality, not just a generalization based on breed that might not actually be true. You can often get pure bred or close to it, with or without papers. So you still have your breed generalization, but I think the fact that they get to know the dog personally is more telling. They figure out which dogs do well with kids, or cats, or what kind of home they need. So you truly get the best fit for your family.
My parents got a rescue dog for my sister when she was younger (I was out of the house). They had gone online and picked out their favorite from the pictures and descriptions, and her heart was all set on it. They went down there for the consultation and after doing an interview with my family, the person who worked there suggested that they meet this other dog. She swore that they seemed like they would be a perfect fit. The dog was bigger and older than my sister wanted so she didn't want to bother. But as soon as she met that dog, it was an instant bond. The fit with my family was as perfect as if she had been designed for them.
Anyway, I just wanted to explain how the rescue thing works, since the idea of a pound dog can be intimidating, especially with kids. But I really think that if you want to know what you are getting in advance, a rescue society is much better than a breeder, a pet store, or a pound. And it is nice to know you are saving a dog too. Also, I second the comment about a low-shedder. I have a lot of pets and a LOT of pet hair in my house. I think I'd shave them all bald if I could :) Good luck on your hunt!