4. The Long Song
http://www.youtube.com/watch?v=X21JXIO-Tec During David Tennant's era, the Doctor's musical theme was whispery, enigmatic and evocative. It made sense for a man steeped in such mystery and mythology to only be associated with the spaciest of sirens singing a single "ooh". But when Matt Smith became the Doctor, he was suddenly scored with an adventurous melody that rung in Whovians' ears long after episodes had ended. The transition from lonely god to fairytale hero can be shown in those two pieces of music. Tennant's regeneration was soundtracked by the huge Vale Decem. The same "ooh" riff magnified by a full orchestra, it was a lot like 'The End of Time' itself. But Matt's regeneration instead brought 'The Long Song', a track that played during his speech in '...Akhaten', but one that summed up his time in the TARDIS. It's optimistic, but it's tinged with a saccharine sadness. It's both hugely moving and empowering all at once, as the lyrics sing the Eleventh Doctor to sleep; "Rest now, my warrior. Rest now, hardship is over." The impossible war ended, and the Doctor died in peace to the most wonderful hymn.