"No, Not the Mind Probe!!?!"

Day Two: Your Favourite Classic Series Episode

Right, well that would be Part...Three, I think, of The Creature from the Pit, whichever one it is where Tom and Lalla are nudging each other in the background and...

Yes, yes I know I'm by no means the first person do that rather lame joke... I'm assuming this means Favourite Classic Who Story, and well, that's a bit of a hard one, isn't it? I was going to give some cop-out answer or maybe a top ten countdown, but instead decided that I should try to answer the question in the spirit in which it was posed. So...