I have always thought that SAP's Hasso Plattner is a good public speaker.  This year at SAP Sapphire, Hasso spoke about column databases.  I was watching his talk again this past weekend and would recommend that if you have some time, you watch this too.  Very interesting.  You can read more here: http://www.sap.com/community/sapphire2009_data_storage_hasso_plattner.epx or watch the video here: http://www.sap.com/community/showdetail.epx?itemID=17716.