I think that largely depends on your lifestyle and needs. Labs and goldens are very popular because they have a strong need to please humans. They are athletes and need exercise. Bassets are large dogs on short legs. They tend to be mellow and easy going. I have a Bassador (a basset hound x Labrador retriever mix). He is more lively than a full blooded basset but not as much as a lab. Spaniels are also wonderful dogs that are toward the medium side. If you want a specific breed or type of dog (like a sporting dog), check rescues in your area. They are can match you with the right dog. Puppies are awesome but a ton of work. Older dogs are most often already house trained and fully grown. Senior dogs are also great because they tend to be mellow and love attention.