The performance in video of Toccata and Fugue is just wow! Incredible, to say the least. It's a total must. I've always loved it because it reminds the old gamer in me of Sabrewulf's theme in Killer Instinct for arcades in the 90's. Also, I can't wait for The Well-Tempered Clavier's Prelude I (C Major). It's almost corny these days but it's still such a marvellous piece, it instantly talks to your body and you know that's beauty being played back to you.
I really can't decide if the music, the organ or the performance was more impressive! As the final notes faded away, I realised I had been crying for most of the piece. It was truly beautiful in every aspect.
EDIT: nearly all his work on The Well-Tempered Clavier is awesome, it's worth a whole afternoon listening to it http://en.wikipedia.org/wiki/The_Well-Tempered_Clavier