IMHO George Roberts Casting Video
I know most of the people from the NE area are familiar with this tape. In light of the casting clave attendance and the number of us who are relatively new to the subject, its a good time to mention.
I picked it up a couple of months ago knowing I needed to do something to correct some bad habits. I've viewed the tape several times and am amazed at how well it's put together. The title, "10 Steps to Power and Distance" had put me off previously - thought it was for the more advanced caster. Not the case. Strong presentation of the fundamentals in a very understandable, technically accessible way. A big thumbs up for the the beginner or the experienced caster who wants to get rid of that hitch in his cast.