If you do not have time to exercise your dog daily with a brisk walk and lots of running choose a breed that does not have high exercise requirements. All of the breeds who require high amounts of exercise make terrific jogging, hiking, and ridding companions. So if you want your dog to accompany you on long runs choose one of these highly active breeds built for endurance and as much exercise as you can throw at them - they will love you for it (and a tired dog is not destructive).
Most all dogs will get along well with children if they are raised with them. However, some breeds have a protective streak in them and may become aggressive with children who get to close at meal time (although this should not be tolerated), or aggressive with children they have never met. These breeds will likely see the children as being underneath themselves in the "pack order" and may try to dominate them.
The following list uses a wide interpretation of "breed." Breeds are usually categorized by the functional type from which the breed was developed. The basic types are companion dogs, guard dogs, hunting dogs, herding dogs, and working dogs, although there are many other types and subtypes. Breeds listed here may be traditional breeds with long histories as registered breeds, rare breeds with their own registries, or new breeds that may still be under development.
That’s why we need breeders of purebred dogs today. People who breed to preserve dog breeds are usually hobbyists. They may participate in dog shows or companion/performance events with their dogs. The dogs that they can’t keep are usually placed in pet homes. Yet cities and state legislatures are passing laws that can make it virtually impossible for smaller breeders to continue this important work.