There might be some episodes I enjoy more than these, but these are the ones I admire for their ingenuity and risk taking. Basically, these are the episodes I couldn't stop thinking about days after first watching them.

1. Human Nature/The Family of Blood - I absolutely adore the idea of this one. It works perfectly for the 10th doctor, who has always favored a more human portrayal. John Smiths despair breaks my heart to this day.
2. Gridlock - Again, a genius idea. If there's one thing I really love about RTDs era, it's how real and relatable his world and side characters feel. This episode only works so well for me because you can't help but love and root for the characters.
3. Midnight - This one is just fascinating. The whole episode is basically an argument between a group of people. The way it gets so completely out of control is a brilliant study of human nature.
4. Vincent and The Doctor - This one is here for the emotional gutpunch. No matter how often I watch this episode I am sobbing by the end of it. I wish with all my heart that this one had actually happened in real life.
5. World Enough and Time/The Doctor Falls - I adore this final. I'm not a fan of epic stakes and enormous casts. Doctor Who always works best for me in an intimate setting. This is a story of absolute despair with people fighting against impossible odds. Without hope, without witness, without reward, indeed.
6. Blink - Again the small cast is what makes this for me. Their interactions and the way Moffat works time into this story is the perfect example of timetravel done right.
7. Forest of the Dead/Silence in the Library - There is so much going on in this story, the fact that it works so well is astonishing really. I still remember being blown away by the twists and turns of these episodes.
8. The Doctor Dances/The Empty Child - I love the setting of this one. The consequences of war are beautifully explored in this. And the child is simultaniously creepy and still utterly relatable.
9. Dalek - This is the story that made me fall in love with Doctor Who. The buildup of tension is great here. For me all other Dalek stories fall short to this one. No other makes them so terrifying and yet so heartbreaking.
10. Heaven Sent - The guts to make this episode, to have the doctor completely alone, wow. This is the perfect example of what happens when people love their work and bring their absolute a-game.

Honorable Mentions: Waters of Mars, Listen, Mummy on the Orient Express, Turn Left, and so on. I could probably find something to adore about every episode of Doctor Who. I love that the writers have such creative freedom.

I've only just started the classics so this list might change in the next few months.