While I'm on the subject of responsible breeders, here is a timely video about a puppy mill bust that shows the polar opposite of responsible. It's worth the 18 minutes but I warn you, it's hard to watch: CAPS vs. Bauck
It serves as a warning to breeders - be careful to whom you sell your puppies.
As a puppy buyer, don't support commercial breeders like this by avoiding purchasing at a pet store or from the classified ads. Research, research, research. Take your time, interview breeders and don't rush when searching for your next companion. Don't be fooled by the misconception that by buying that puppy in the window you are "saving" it. You are perpetuating the problem. It would be much better to visit your local shelter or rescue group.