SIGGRAPH is expanding their speakers this year to include some different areas. They announced a while ago that the CTO of EA would be a speaker, and they just announced that another speaker is going to be Scott McCloud. Pretty cool.
They say there are going to be three featured speakers. Since we've got one from games and one from comics, I wonder where the third one is going to be from. Movies have already been an integral part of SIGGRAPH, otherwise I might guess it would be some Hollywood type. Nothing else immediately springs to mind, though.