Newfoundlands, which were originally bred to be working dogs in the cold North Atlantic, consistently rank as the kindest, gentlest, best-tempered purebreds in the world. Newfs are also enormous (up to 150 pounds!) and one of the strongest dogs for their size, but their legendary patience makes them very suitable for families with small children. This is the dog to trust if your baby ever needs to be saved from an icy river.
However, their sweetness comes with a price: maintenance. Their thick coat needs brushing at least once a week, and it's no use denying that Newfoundlands are slobber factories. They also need plenty of space -- a moderate daily walk will take care of their exercise requirements, but make sure to have enough room indoors for them to sprawl out on the floor afterward.