Das Rheingold by Wilhelm Wagner
(The Ring of Gold)
[youtube:2m7i0lfw]http://www.youtube.com/watch?v=wiyoLa9z1ao[/youtube:2m7i0lfw]
So gorgeous. This reminds me of the BN intro. Of course, not at all the same and this is slower, but it puts me in the same frame of mind where you just want to slip into all that beautiful sound as it builds and builds.