Coronation Anthem: Zadok the Priest
This was performed at Buckingham Palace in 2002 by BBC Symphony Orchestra and Symphony Chorus. The music conductor was Sir Andrew Davis.
http://www.youtube.com/watch?v=p1W1XJ96y9k
Messiah: Hallelujah
This was performed in New York City 2004 by Johann Strauss Orchestra and the Harlem Gospel Choir. The music conductor was Andre Rieu.
http://www.youtube.com/watch?v=76RrdwElnTU
Messiah: Hallelujah
This is actually my favorite, because it's a pleasant surprise presented by the 100+ flash mob participants at a food court on Nov 13, 2010. Very heart warming!
http://www.youtube.com/watch?v=SXh7JR9oKVE
Concerto Grosso Op 6 No 12 - 2. Allegro
This was performed by the string orchestra of the Fundación Universitaria Juan N. Corpas on 30 August 2007. The music conductor was José Miguel Serrano.
http://www.youtube.com/watch?v=0p8PaM2GuRI