In reply to J_D_P: I hope I haven't offended anyone - that was never my intention. I was thinking aloud about how he came by the title Dr, as this is a protected title for good reasons (to stop the Gillian McKieth's out there).
About chiropractice in general, the evidence (/lack of) is out there and people can make of it what they will. There are interventions that have limited evidence basis but seem to work. From my point of view I enjoy looking at the various evidence bases for treatments, and questioning those without a solid grounding in research - that is how we progress. A quick search on chiropractice on pubmed threw up this article "Chiropractic: a critical evaluation."
http://www.ncbi.nlm.nih.gov/pubmed/18280103
"The concepts of chiropractic are not based on solid science and its therapeutic value has not been demonstrated beyond reasonable doubt."
I shouldn't cherry pick papers however from the limited reading I have done I understand that chiropractice is not based on rigorous theory or evidence based research, and as such I will remain sceptical about the efficacy of any treatments offered by such practictioners.
With regards to your last point on questioning somebodies qualifications - this is vital! Personally I do not want someone performing spinal manipulation on me without knowing exactly what their qualifications are!