For information about the temperament used in Watchorn's recording of the Well-Tempered Clavier, based on an examination of (I kid you not) the spirally ornaments on the title page of Bach's manuscript, see http://www.larips.com/ . (Why "larips"? Well, you see, the analysis begins by looking at that title-page upside down, and "larips" is "spiral" backwards. Again, I kid you not.)

It sounds pretty good, actually, but so do plenty of other temperaments.