Canton is by far the best person who is not part of the TARDIS Crew who has helped the Doctor ever. Craig Owens was good and so was Vincent Van Gogh and Winston Churchill but Canton is so much better. And he got the best lines!
"Welcome to America." After shooting the Silent.
"Looks aren't everything." Before he 'shoots' Rory.
And others that I can't quite remember at the moment. He is AWESOME! 'Nuff said