6. The Robots Of Death (Fourth Doctor)
Sometimes a theatrical name for a story is good. Unless of course, you're filming a murder mystery, and you name it The Robots of Death. Kinda gives away the ending... Nonetheless, this is a stellar Doctor Who serial, with some excellent atmosphere to it. The fourth Doctor and his new companion Leela land in a mining ship, unfortunately at the exact same time the crew finds one of their own murdered. They are held under suspicion until another crew member is murdered, but of course this time they have an alibi. What follows is four episodes of investigation, murder, and sabotage. And while the title completely gives away who doing the killings (the robots), there's still more to it than that. Hmmmm....
5. The Doctor's Wife (Eleventh Doctor)
The single best episode of the 11th Doctor's run, this episode was penned by legendary writer Neil Gaiman. This episode serves as his love letter to the show, and gives us something all fans never knew they wanted to see so badly. When the TARDIS receives a distress call from a Time Lord named the Corsair, the Doctor is ecstatic. Having believed all the other Time Lords to be dead, he sets out at once to find the Corsair. What he finds instead is a living asteroid that feeds off TARDIS energy. When the asteroid (named "House") learns this is the last TARDIS, it ejects the soul of it into a woman's body, and takes off - with Amy and Rory still inside. After the initial shock of being able to talk with his beloved TARDIS, they begin working together to build a new TARDIS so they can pursue House. And this all builds up to the epic confrontation between the Doctor and House. https://www.youtube.com/watch?v=shKS8bYeFmg