David Calof has been mentioned a handful of times on this forum but I don't think Hypnotic Techniques has been reviewed here (apologies if it has already).
It was originally a set of 6 audio cassettes but is currently available as a CD or MP3 download. At US$80 it isn't cheap, but I think it is fantastic.
I started listening to this when I was very new to hypnotism and really liked the seminar style of the sessions. I also really like his accent.

At one point I had the entire set on my 6-CD changer in my car and and spent about two months listening to it over and over again (driving about 400 miles a week at that point). I can't say I've ever got bored of it; like many good things, there is always more to discover the more you look. (I could practically quote it by the end of that particular job!)
He was a student of Erickson and, I believe, was one of Bandler and Grinder's 'inner circle' at the beginning of NLP. Grinder has been quoted saying nice things about him. He teaches permissive and direct hypnotism, flexible induction and therapy techniques plus a number of cool patterns and metaphors that he suggests can be used in self hypnotism.
There is so much to it that I can't think of which parts to emphasise. It's up there with Patterns 1 in my opinion and it is the source of the eyes-open card drop routine that I've been rolling out for years and James Tripp recently wrote up and developed. Lots of left hand, right hand, adult you, child you, left brain, right brain, conscious, unconscious dissociative patter and explanations.
He sounds like a great guy, very friendly and so hypnotic. Totally recommended.
AchievingExcellence.com appears to be the official supplier.
Kev