Stahleck and Schonburg             
I must be honest:  Stahleck and Schonburg never really excited me when I saw them years ago.  I have yet to visit Stahleck, but I did make it to Schonburg on my 2005 trip.  I'm not even sure if Stahleck is open for visitors.  One source indicates that the courtyard is open, and I believe there is a youth hostel located there. 
The castle dates back to the 1100s, the owners and their successors also building Gutenfels, the Pfalz and Furstenberg.  It was destroyed in the Thirty Years War, rebuilt only to be destroyed by the French in the late 1680s.  The castle sits above the town of Bacharach which is well worth a visit.  Left, in 1978 and below, in 2005 from Bacharach.
I finally made it to Schonburg on this trip, only to find that it housed a hotel.  You can get inside the courtyard, but I do not believe it is open for touring.  Nevertheless, it did provide some good photos, especially when compared with my shots from the late 1970s.  It is clear that some retoration work has been done.

Below in 2005, below right in 1978.
Schonburg was started in the 1100s, and then received successive expansions and rebuilds as witnessed by its three different courtyards.  Occupied in the Thirty Years War by different forces, and destroyed in 1689 by the French, its rebuilding started in the 1880s.  Schonburg is unique because of the curtain wall that guards the entrance (right).  Below left, part of the curtain wall from within. Below, a forboding view of Schonburg from Oberwesel.  At first the weather was very poor, but cleared up some by the time I got to the castle.
The view up the Rhein (looking south) from Schonburg.  Unfortunately, the mist was so heavy that even my filter had trouble cutting through it.  The Pfalz is visible in the distance in the middle of the river, while Gutenfels is barely visible above it.  Nevertheless, an awesome view!
A nice view of Stahleck from Nollig, on the opposite side of the Rhein.  Such views demonstrate how close these castles were to each other, and the fact that the owners in large measure lived at peace with one another, contrary to the image often painted in modern history books, that the medieval period was one of constant violence and warfare.

An interesting note about Stahleck.  Most of the roofs are fairly new, as prints that are over 100 years old show the castle without them.  Therefore, the roofs are fairly recent additions.