Jeffrey Trimble writes:
 
        Here's my $.02 worth.
 
         [ ... ]
 
        I will mention the next one as a reference source (not all that
        authoritative for interpretation) is the Complete Organ works edited
        by Marcel Dupre.  Don't laugh.  This has some of the best fingerings
        I have ever seen--and not all fingerings work for every performer! I
        have used some of those fingerings for passages I was about to give up
        on, since I like to finger passages based on articulation and touch.
 
I agree - the Dupre editions are worth having for reference - I learned
most of my Bach from the Dupre editions and found them very useful for
exactly the same reasons.
 
The Novello editions which were probably about the cheapest Bach editions
available in the UK are, I think, definitely to be avoided (although some
of the suggested registrations are amusingly Edwardian - you know the
kind of thing "Great to mixtures + Full Swell with the box shut" .....)