7. The Eleventh Hour
For me, this is the absolute best post-regeneration episode ever. Matt Smith had some pretty big shoes to fill, coming on the heels of one of the most popular Doctors ever to play the role. But within the first five minutes of the episode, you're totally on board with him. If you were worried about him being too young for the role, that's the furthest thing from your mind right now. He comes off as a breath of fresh air, a youthful burst of energy after a Doctor who had been so wearied by the time he regenerated. His interactions with young Amelia are priceless, and you can at once see how he's different from his predecessor. For some reason, I can't imagine Ten sitting down and having the conversation Eleven has with Amelia about the crack in her wall. There's a subtly different vibe to the situation. While the Prisoner Zero story isn't the strongest, I love how it brings Amy and Rory into the fold. Interestingly enough, although Amy is the primary companion, Rory is the one who seems to intuitively realize that something weird is going on and investigates. They're a great team, right from the beginning.