In 2002, a short while after I started at MySQL (http://mysql.com), I saw Lawrence Lessig present at OSCON. The presentation was extraordinarily good and Lessig is a tremendously passionate, genuine and compelling orator.
I immediately revised my presentation style. I stole what ideas and style I could. While I was mostly presenting about MySQL and PHP at the time, the ideas served me well (though the style has at times fit me about as well as a young child fits their parent’s clothes.)
Five years have passed since then, and I have given a hundred or more presentations. Never have I presented as well as Lessig that night, but I still keep trying. In a few days, I am going to have to try a lot harder.