Concerning the comment in the second episode, Ash was only ten then and much too young to know the truth...although it seems that Ash's father ran off, Delia might have wanted to hide the truth as to keep Ash thinking that his father was gone away on pokemon business, so she could have easily said that just to make Ash feel better. Giovanni is the most likely choice, even though there is no proof. I like the Luke/Vader parallel with Ash and Giovanni, how your worst enemy turns out to be your closest relative...also, I'm sure that they're saving huge revelations for the end of the series...major things that would happen would include Ash's father being revealed, AAML coming into plain view, things like that...Giovanni being Ash's father would make a very interesting occurance for the finale...if they were to reconcile somehow or Ash bring down TR entirely, I think it would be good because it would release Jessie and James from the miserable line of work they're in, Giovanni's ambitions would be crushed as well, and he could either choose to hold a grudge against his son or embrace him and go back to Delia to unite the Ketchum family once again. It would just make the best dramatic ending to the show, and that's why I think that he's Ash's father.