The Krotons (Second Doctor).
Robert Holmes' first contribution to Doctor Who and it's a good one despite the fact that that Krotons themselves were so poorly designed by the art department. The concept of a race of creatures, robots?, made of a crystaline material is interesting. It's just too bad they were so ackward. It was also good to see Philip Madoc again, definately one of Doctor Who's players for all seasons. I Liked how his character arc wasn't resolved in the end, it's something that will have to be delt with by the population after the Doctor leaves.
Horror of Fang Rock (Fourth Doctor).
A good old fashioned horror story, shape-shifting monster and all. The confined lighthouse set worked to the episode's advantage. The guest cast also did well but I was waiting for both Lord Palmerdale and Adelaide to kick the bucket. I was surprised however that everybody except the Doctor and Leela was killed off. In the beginning I figured at least one would survive to tell the tale.