2. Wil Wheaton
Wil Wheaton came to the attention of science-fiction fans as Wesley Crusher in Star Trek The Next Generation and since leaving the show has done many things including writing, podcasting (Radio Free Burrito), gameplay and blogging - he won every category he was nominated for in the 2002 'bloggies'. More recently he has come back to the attention of TV audiences first as 'evil' Wil Wheaton and then simply as Wil Wheaton in the show Big Bang Theory. Wil has a good pedigree of playing in genre and would be a major cross-over event were he to become everyone's favourite Gallifreyan. He would also help ensure the continued US interest in the show and therefore its longevity.