Heikki,
 
Have a look at The Notebook for Anna Magdelana Bach.  Kalmus publishes one and
several others are around.  Mostly music suitable for home playing, although it
does contain some more complex material (i.e. French Suite in C minor.)  The Bach
scholars heatedly debate just how much is from J. S. and how much from the
venacular literature.  It doesn't really matter -- this music was for the
personal entertainment of the performer.
 
You didn't say what kinda of music interests you and most suggestions you get
will probably reflect the various writers' own interests.  Bear in mind that Bach
is especially difficult at every level, much in part due to his profundity.  One
can invest a fortune in music (many of us already have!) and still not have a
representative library.  The list discussed the Telemann Fantasies recently
(Dover Edition).  At their most difficult they are far easier that most of Bach!
 
Personally, I thrilled that you are learning to play the instrument.  I'm rather
new to harpsichord playing, having done most of my previous work banging
contemporary music on a Neupert.  I've played the organ, however, for over 40
years and continue to develop repertory on that instrument.  Piano has always
been my love, however, and I play most of the literature for that very versatile
instrument.  For the past 15 years I have mostly played chamber and ensemble
music for piano and in that context have learned a fair amount of the trio sonata
and other ensemble literature that was by habit played on the harpsichord.  By
all means immediately find a couple of violin players and a cellist and learn
some Corelli Trio Sonatas.  The keyboard parts are often quite simple.  The
difficult passages can be learned far quicker than a Bach Allemande!  And when
you play them with your friends you will discover what a great treasure we have
in the the chamber music literature. Also, Peters Editions publishes a wonderful
volume of Hausmusickstunden that is a bit more demanding but still possible for
amateurs.
 
Remember that during the Baroque all organists played the harpsichord and much of
the literature is interchangeable.  Such collections as the Pachelbel Fugues on
the Magnificat (Dover edtion) contain as much harpsichord literature as music for
pipe organ.  I think they are much more accessible than the Bach Inventions and
Sinfonias.  The ornamentation (always a stumbing block) is not nearly so fussy as
you find in Bach.  And MUCH easier than the 48!
 
Go to a large music store and have a look at some Frescobaldi (Italian), Couperin
(very, very difficult style to master), Handel (a total delight),  Sweelinck
(Dover Edition).
 
Search the list archives (or was it on the pipe organ list?) for comments about
La Folia.  Learn to improvise around that (or any) ground bass.
 
Good luck!  I hope this helps.