This is a transcription for piano for a piece that is perhaps one of the most famous organ works Bach wrote. I think it's impressive perhaps for its unpretentiousness. http://www.youtube.com/watch?v=oLFLhzb9xzs
I got into trouble with this piece at school. When I was about 13 I asked our organist if he could play this. And he volunteered to do so after morning chapel. I stayed and listened to it and of course was late to class. I was sent off to report myself for this offense and my housemaster didn't believe that I would be interested in such a thing. I was rather a naughty boy. A few minutes interrogation and he realised that under the grime, there was a music lover and I was let off with a caution!