I guess I will get the ball rolling... I am all for chiropractors. I have seen over 10 different chiropractors, and only 2 were suited for me. I prefer the preventative type of treatment over the reactive treatment. I go once a week or every other week. It costs ~$80 a month if I go weekly. Plus my health-care program pays for some of that.
The reason I like the chiropractor I am with is because he explains to me about his theories and how chiropractic allows my body to heal myself, and maintain health. By keeping my spine properly aligned my nerves are free to operate. If I am "out" my nerves may be restricted or pinched, and depending on where in the spine they are located it can affect various bodily functions.
I was getting routine bladder infections. The doctor kept giving me more and more anti-biotics. A couple of months later I started seeing this new chiropractor (for headaches) who explained to me that by adjusting by mid-lower back he can alleviate the bladder infections. Of course I was pessimistic about his claims, but it was true. My bladder infections went away.
Unfortunately with my migraine headaches, there is only so much that chiropractic alone will help. I also have to eat properly, excercise more often, avoid alcohol and smoking. But in my overall health, I think that chiropractic is essential.