Anthony Stewart Head
Anthony Stewart Head was largely unknown in the States when he landed the role of Buffy's bookish mentor Rupert Giles, but he was fairly well known in his native England. Since Buffy, Stewart has worked constantly on both American and British TV screens, often on comedy shows like Little Britain and Sold. In 2006, Head guested on Doctor Who, and would later revisit the Whovian world in 2007 in Doctor Who: The Infinite Quest. In 2008, however, he scored one of his most acclaimed roles as Uther Pendragon on the hit series Merlin and is set to appear in Percy Jackson: Sea of Monsters. Stewart is also said to be on the short list of actors who could very likely become the 12th Doctor on Doctor Who!