I frequently have people ask me this question when looking for a pet for their family. Many families base their decision on a breed they had as a child or based on an individual dog owned by a friend or family member. A number have gone online or purchased a book on dog breeds and try to choose based on the breed description.
Here's the thing about breed descriptions: They all say that a breed is loyal to their owner, that aggression is considered a fault, and that they all need a certain level of exercise.
What breed descriptions don't tell you is that any breed of dog is subject to bad breeding practices, leading to both health and behavior problems.
Breed descriptions don't tell you that if a breeder doesn't socialize the puppies before they get to your home, the puppy could be already starting their life with you at a severe deficit.
Breed descriptions don't tell you that within every breed, there is a vast spectrum of differences in temperament, energy level, and personality.
I have worked with Border Collies who love children...and those that are terrified of them, so not every BC will try to herd children in a problematic way.
I have worked with Golden Retrievers who are amazingly tolerant of everyone and everything....and those who are horrific biters, causing serious injury with one bite.
I have worked with Pit Bull-type dogs who are sweet and gentle and can handle any situation thrown at them...and some who are very dangerous dogs.
Every dog is an individual, whose behavior is determined by a combination of their health and genetics (nature) and their environment and learning history (nurture).
You may choose a breed because you like the look, the size, the grooming requirements (or lack of), and even the general characteristics of the breed. But that should be where your search begins, not ends. And every dog, regardless of prior training history, is still going to need a fair amount of training in your home, while they learn your rules and boundaries.
And breeders are not the only source, either! Almost every breed has a rescue group and most shelters are happy to notify potential adopters when they have a dog of a certain breed or mix come in.
Finally, finding the right dog for your family is going to take time. You can't walk into the Family Pet Mart and pull a perfect dog off the shelf or order one online (please, PLEASE don't purchase pets online...unless you are prepared for higher-than-average vet bills and behavior modification expenses).
If you're not sure how to go about finding a dog that meets these qualifications, enlist the services of a qualified trainer. I absolutely LOVE to work with dog owners looking for their next dog and teach them how to spot both the good traits and the red flags. And it's even better when we find that dog at the local shelter.