18. Labrador — In addition to being one of themost respected hunting and retrieving breeds in the world and the first choice for an assistance dog in the U.S., the Labrador retriever is also the most popular dog breed for a family pet in the U.S. They are energetic, intelligent dogs with a loyal and gentle disposition who are equally at home in cold marshes hunting with their masters or in the living rooms of their families' homes. They are highly trainable as guide dogs for the blind, search and rescue and other service dogs as well as excellent companions for children. No wonder they are America's favorite dog!