Just watched "The Enemy of the World" on DVD. Was a very enjoyable story. A refreshing change of pace for Doctor Who (especially for that era). No monsters. Just the evils of humanity. Not only was Patrick Troughton a really good Doctor, but he played a very evil villain (if with a dodgy accent). As always Jamie was fun to watch, I've always thought him one of the best companions. And I know Victoria gets a bad rap as one of the worst of the screamers, but honestly I don't think she screamed once in this story. Thought she handled her own quite well.
In some ways the Hartnell and Troughton years were the best for Doctor Who: in that there was no show formula. It was still very experimental. By the Pertwee years it became very much a "Monster-of-the-Week" show. Oh there were the rare exception ("Black Orchid" is a lovely example), but on the whole the formula for the show never really changed. And the revived series feels even more trapped in that. While the latest season dabbled in different genres ("Time Heist" was a very good heist story, and "Mummy on the Orient" express with it's obvious homage), even still it never seems to escape that fundamental premise. I have a very hard time imaging them doing a story like "The Mind Robber" today. So I enjoy those years, when it was finding it's identity. Changing from purely a light sci-fi show specializing in historical education to monsters and scares and pure entertainment.