1. Genesis of the Daleks
Well, of course this was going to be on here. Easily one of the best stories of the entire original series, and certainly the best Dalek story of the era. This one introduces Davros who, for better, worse, or both, went on to dominate just about every Dalek story since. This story is rightly praised for being pretty magnificent. Not only does Michael Wisher do an excellent job as Davros, but you also get Tom Baker doing some of his best work on the series and Peter Miles doing a great job channeling Himmler in his role as Nyder. While some could argue that the story makes the Daleks somewhat less interesting and that the whole thing would have been better in four parts rather than six, its hard to deny that this is a truly excellent story.