The Borgias has been cancelled so there's a whole bunch of great actors that will be free for Game of Thrones. The guy that played Cesare Borgia, Francois Arnaud (http://www.imdb.com/name/nm2957696/) could easily fit for a few characters and should definitely be considered. Depending on how young or old D&D want Victarion to be, he could fill that role. Same goes for Darkstar, Young Griff (although I'd prefer Mitch Hewer), or Euron.