I'm voting The Dalek Invasion of Earth - purely because that quote is an all time classic!
I feel bad for Marco Polo as it's supposed to be a belter and we'll never know (cheers BBC!)
(from wiki); Although no clips from this serial survive, a condensed 30-minute reconstruction was included on The Beginning, using production photographs, telesnaps and parts of the soundtrack (which survives and has been released on CD in its entirety).
In fact, you can get the full-length version of that reconstruction, which is absolutely brilliant. Still, maybe just because it exists in full,
The Dalek Invasion of Earth
