pbutler makes a very good point above. At a good multi-day conference, the real deep thinking progress is made after the day's sessions are closed and those who are interested are sitting around the hotel bar or pool or whereever with a good supply of barley-pop and a stack of pizza boxes.

Re good speakers, it depends on the topic, but most I know well are associated with k-state.   One who comes to mind who recently defected to your state university is Randy Taylor.