4. Number 10 Doesn't Want To Go
The final moments of the aforementioned episode show the Tenth Doctor trudging along the world a dying Time Lord. He saves Sarah Jane Smith's son from dying, protects Martha Jones and Mickey from being shot, visits Rose Tyler before she's met the Ninth Doctor, and gets Captain Jack laid. Like he needed any help. That is a beautiful, beautiful man. The Ninth Doctor's exit was full of brash exuberance, claiming that while Rose was "absolutely fantastic", so was he. The Tenth Doctor, portrayed by David Tennant, is less upbeat about his impending demise. As he watches his injured body begin to regenerate, the Doctor reflects on his recent past with his three companions and says to himself "I don't want to go" before exploding into a ball of energy. Number Ten is reincarnated as Matt Smith. He's instantly appalled at his chin size but quickly becomes comfortable with a wardrobe of bow-ties and a brand new sassy redhead to follow him around. And speaking of sassy redheads, let's check out number #3...