4. Casanova
Before he was the Tenth Doctor, he was
Casanova! David joined forces with
Doctor Who's then incoming showrunner Russell T Davies back in 2005 to tell the tale of history's most notorious prowling sex pest. The 3-part comedy drama was based on the legendary lover's very own twelve-volume memoirs and brought to life the various post-watershed shenanigans he got up to during his less than humble beginnings as the son of an actor in 18th century Venice. David obviously left a lasting impression on Russell, too, since he later reinstated him as the Tenth Doctor. Needless to say, his jaunt as TV's favourite Time Lord was far less promiscuous. OK, so that's debatable.