I’m currently making my way through all the stories I’ve got and then never watched because of various reasons (life got busy!)
I started with The Sensorites (really enjoyed it) and The Reign of Terror (good story but the god-awful animation of Eps 4 & 5 ruined it for me).
Im now watching The Enemy of the World before moving onto The Krotons, The Ambassadors of Death, Colony in Space, The Daemons, The Mutants, Invasion of the Dinosaurs, Death to the Daleks, Terror of the Zygons, The Android Invasion, The Masque of Mandragora, The Face of Evil, and The Robots of Death.
The last 3 I saw when I was a lot younger on UKTV at about 4am so I don’t remember them at all!