He's hilarious. And I feel just sooo bad for him, especially at the end when he saves the Doctor and starts shooting lighting at the Time Lords. I feel for him. Also, the introduction of him as Professor Yana was freaking epic.
Doctor Who Special: "Time Crash" - A missing scene between the end of season three and the start of season 4, in which Ten and Five meet in a time crash!...Because this is Tennant at his finest, being the fanboy he truly is, talking to the Doctor who made him the Doctor he became. It's so much of the truth...made into a story, just as stories ought to be.