I have presented and facilitated hundreds of workshops and given many keynote addresses. I know that the success of your event will rise and fall with the effectiveness of your presenters and workshop leaders. Today more than ever people expect a presentation to be relevant, authentic and engaging.
An added benefit is that participants can have a tangible piece of their learning by taking home either of the books, depending on the topic:
The Choice to Show Up by Mark Freier
The Execution Culture by Chris Elias and Mark Freier