4. Vincent And The Doctor
This is to date one of two Doctor Who episodes that have made me cry. You might argue that making people cry isn't necessarily the function of Doctor Who, but I think having that much of an emotional connection shows that the actors and writers were doing something right. Tony Curran knocks it out of the park as Vincent van Gogh, and it's hard not be touched by his story. Amy is at her most likable in this episodes, as she immediately bonds with the misunderstood artist. The cinematography is gorgeous, and Doctor Who has never looked more vibrant and alive. Add in a well-placed cameo from Bill Nighy and a perfectly executed commentary on mental illness, and you've got one of the best episodes that's come out in years. It might be a bit less science fiction than most people like their Doctor Who, but for me it hits all the right notes.