To me a good breeder breeds to produce dogs that are good representations of the breed standard. They breed with emphasis on health and temperament--not size or traits that vary from the standard. They do health testing and ensure they are not breeding and passing on genetic issues. They place their dogs on s/n agreements. They don't overcharge or breed just to make $$$. Their dogs are well groomed, well cared for and not living their lives in kennels or cages and are properly socialized. They don't release their pups at an extremely young age, they carefully screen homes where their dogs are placed, offer health guarantees and go the extra mile to help educate and assist the new owners when needed.
And then there's everyone else...