For the 19th consecutive year, the Labrador Retriever has held on to its title as America's "Top Dog," according to the American Kennel Club's (AKC) 2009 registration statistics. In a nod to watchdog breeds, the German Shepherd Dog overtook the Yorkshire Terrier to claim the spot of "second most popular pooch" for the first time in more than three decades. An American favorite since the time of Rin Tin Tin, the German Shepherd Dog became the number one breed of the 1920s, but then slipped in popularity until after World War II. The German Shepherd Dog isn't the only working...