So with The Christmas Invasion we bid farewell to Nine and usher in the era of the Tenth Doctor. There's a number of moments from TCI that could fit here -- Rose's distress over Nine's death, the Doctor springing out of a coma because Rose asked for help, holding hands in the "snow" -- but ultimately I settled on this:
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It's really quite apt that "Song for Ten", despite being, well, for Ten, is much more about Ten and Rose together, since that relationship will be so crucial to the entire story of the Tenth Doctor. Plus, it's pretty cool that Doctor/Rose gets their own song. (Songs, even.)
As for The Christmas Invasion itself -- what did you think? A good introduction to the Tenth Doctor? Were you as wary as Rose?