If you have a large house with a large yard, any type of dog would probably be good. However, if you have a apartment with no yard, you need a less active dog that doesn't require as much exercise as a large, active dog. Dogs are very social pets. They will require your time to play, groom, exercise, and train. If you are not at home most of the day, and the dog will be left alone, consider another type of pet.
Dogs require yearly shots, grooming, toys, and food.
Puppies will cost more at the vet initially. Some types of dogs require more grooming than others and are more prone to have health problems, which might be costly. Another consideration is food - large dogs eat more than small dogs. Think about these costs before you decide what type of dog you want. Dogs are social pets that need attention to be happy.