8. The Joker (Batman)
Cesar Romero's Joker, whilst being an awkward foe for Batman and Robin, is simply far too small-time to pose a threat to the Doctor. His goofiness, whilst also sometimes quite sinister, would be nothing more than a mere annoyance to a man who operates on a much larger scale than Gotham's biggest prankster. Of course, Joker himself would think otherwise. He's too cocky and confident to not see himself as a threat to the Doctor. But, having proved himself to be beatable by Adam West's Batman - a resourceful individual yes, but operating at 'street level' nonetheless - he'd stand no chance of out-witting the Doctor. Heck, he could bring in the rest of
The United Underworld (Penguin, the Riddler and Catwoman) if he wanted. They still wouldn't be in the Doctor's league as a collective. I mean, can you imagine how easily the Doctor would solve one of the Riddler's riddles? It would like a very slow Tuesday for him...