I would never get a docked dog if buying from a breeder (but then I would never get a dog from a breeder) - I don't know enough about working injuries to pass informed judgment on the docking of working dogs as long as there is enough tail left for the dog to wag (reasons for that in a bit).
Ear cropping, in my opinion, is something which could never be justified. It has been perpetuated in fighting dogs; a dog with hacked up ears has one less part for its opponent to grab hold of.
(There's a line on Wikipedia, which may or may not be fact, but if it's true it's utterly terrifying;
"American veterinary schools do not generally teach cropping and docking, and thus veterinarians who perform the practice have to learn on the job.")
The way I see it, dogs use their tails and their ears in the way they communicate. Things like mood, discomfort, fear etc are displayed through wagging/tucked in tail and upright/folded back ears. Even looking past the unnecessary risk of infection with the actual procedure (especially if done by the breeder and not a trained vet) the resulting product is a dog who cannot express itself the same way as other dogs. That's hugely wrong.
Whilst we're talking about America, animals, and terrible practices. A bit off-topic, but I keep ferrets, and hear tales about Marshalls ferret farms - an organisation who breed ferrets to send them out to pet stores around parts of the US. These ferrets are 'desexed' and 'descented' at 6 weeks. Yup, weeks. Here in the UK vets won't neuter ferrets until about 6 months (sometimes a little earlier; but generally the later the better.) As a result, American ferrets have an expected life span of 4-5 years. British ferrets live twice that, with an expected life-span of 8-10 years.