I think a great topic for your pod-cast would be "Character Alignment"... this is a topic that everyone see's differently. Each edition describes it differently and most DM's don't really have a good grasp on how to use it in a game well.
I personally think Alignment is the CORE of Role-Playing and forces the PC's to adhere to some set of rules .... while others feel alignment could be removed completely.
Anyway... that's my two cents