4. Captain Jack Harkness
Star of adult Doctor Who, Captain Jack Harkness, ex-conman, leader of the old Torchwood 3, undying, potential Face of Boe and friend of the Doctors, Jack has done a lot except return in the Moffat era. He was meant to return in A Good Man Goes To War but was unable to. Love him or hate him, I would always welcome him back to our screens along with Gwen Cooper, by the amazing Eve Myles. Also, with Torchwood Series 5 not even in conception yet, Im sure John Barrowman would love to come back.