I think having a poker player is a waste of time IMO. I would much rather go to the conference and see someone like Brent Hoberman (the speaker in London). I am more in favour of an entrepreneur that has made a successful living out of the Internet by doing something innovative. Sure, poker players would probably have some interesting stories, but listening to an entrepreneur is much more inspiring.
Also, I like the recommendation of Matt Cutts. It would be nice to get inside the head of google to see how they look at our industry.