Usually the photogs I know fight to AVOID shooting speakers.
Yesterday, I got a call from my editor who couldn't make (another) one of his shoots. I accepted and it turned out the speaker was none other than Grant Imahara, of Mythbusters fame.
Somewhere around ISO 2000. The exposure was far from perfect, so you can see the grain fairly obviously... Oh well.
I sat right in front of him for the majority of his presentation, snapping away. He was a fairly amusing speaker, with a bunch of funny stories about his work with Jamie and Adam and the things that blow up when they work together. The topic of his speech was engineering's role in the entertainment industry. I found that fairly dull, but I still enjoyed the experience.
I stuck around afterwards to talk with the reporter and see if Grant would be doing anything afterward. I wanted to get a decent portrait of him. No such luck, but I did wrangle a ticket to an exclusive reception where he signed some autographs and chatted it up with kids from the local robot club and their ridiculous parents, most of whom were just as excited as their kids.