A Great Big World f/ Christina Aguilera "Say Something" (Christopher Sims, dir.)

The presence of Christina Aguilera on this gorgously stripped-down pop ballad threatens to drown out brainy NYC duo A Great Big World, much in the same way that not many people noticed Mikky Ekko on his similarly fantastic Rihanna collaboration.

That said, Christina has already invited them to perform with her on The Voice, while also providing the name recognition that will open many mainstream radio and pop radio doors. And, unsuprisingly, she hits all the notes perfectly.