I don't have a favorite "clinician."
What I mean is, I don't have an interest in the types of trainers who just go around and do "clinics" and push their training programs (and related merchandise) at every horse expo in the country.
The best clinic I ever rode
in was done by three-time Olympian Michael Page, hosted by The University of Findlay (northwestern Ohio). In my case, it was because the clinic was a huge confidence boost. He had me doing courses and fence combinations that I might have never even tried on a "normal" lesson day with my regular trainer. Not to mention that the man is a class act; friendly, very easy to talk to and approachable, and a wealth of knowledge. . .with a great sense of humor, too.
One of my favorite clinics that I've attended was by Scot Hansen, it was a "Self Defense for Trail Riders" clinic. Not so much a focus on training the horse itself, but learning how to use the horse's size and movement to protect yourself if you're out on trail and someone tries to pull you out of the saddle.
I haven't been to an expo in a couple of years, but I've always preferred the types of clinicians there who specialize in a specific area (dressage, hunter/jumper, gaited horses, etc.). Even if it's not an area I'm specifically interested in, I get a much better appreciation for that particular discipline by seeing someone who actually knows something about it, teach it to others.
These are the trainers who go back to their own barns and still have client horses to train for an upcoming competition, or students to teach, horses to feed, and shows to prepare for.
This was mentioned a while back, but I do find it disappointing to attend some of the larger horse expos and go to see a clinic with a very successful, talented trainer of a specific discipline, and a very small audience. And it's not because those trainers have nothing worthwhile to share.
Then, the BNC shows up and it's a packed house of people watching what is basically a live commercial to promote their DVDs, books, and gadgets.