As previously mentioned, one of my favorite composers is Dietrich Buxtehude (1637-1707).
This video is of Jens Korndoerfer playing The Prelude in D during the first round of the 2008 Canadian International Organ Competition.
The organ is a 1961 Rudolf von Beckerath Organ
I have listened to several performances of this piece and I doubt there is one that I like more than this version. Bravo, Jens.