After seeing part of Damian's Presentation Aikido and the result of his preparation in his talks, and also after seeing the huge difference in how well received my Black Magic talk was in Toronto and how others of my talks were in other places...
I came to the conclusion that spending a good deal of time preparing slides and jokes really pays.
Hence, I am now in the process of redesigning my Black and White magic talks.
Relax, I'm not thinking of putting you guys again in the Black talk
I'm also thinking about a new talk.
Bottom line: instead of preparing 5 talks with one or two days notice, I'm preparing 3 talks with several months time (I hope) in order for the audience to get the best from them.
I think I'm on the right track.