My favourite pop song of the 21st Century also has the most beautiful pop video of all time. The song is "Fighter" by Christina Aguilera and the video is directed by Floria Sigismondi.
(Yes, I edited this post because the original link I had here was to a copy of the video on YouTube. I've replaced it with a link to Floria Sigismondi's own site. - I corrected my misspelling too.)