Just finished hosting a great 4 day workshop with Jimmy Clewes.
Jimmy inspired and coached as well as leading and teaching.
Matching your desires as a student with what instructors offer is the key.
I have had the good fortune to take and host a number of workshops.
I would recommend Al Stirt, Trent Bosch, Jimmy Clewes, and David Ellsworth as excellent choices for any wood turner at any level.
For someone with a special interest Dixie Biggs, Christian Burchard, Cindy Drozda, Clay Foster, Larry Hasiak, Lyle Jamieson, Johannes Michelson, and Michael Peterson are hard to beat. For example I would reccomend Johannes to anyone interested in thin walls or hats.
There are lots of other great folks too.
Happy turning,
Al