Here is a list of some nice castles-turned-hotels in Europe.  The one that is listed in Ireland was owned by my ancestors.  It was neglected by the 20th century, though, and title was passed around (including to my uncle, but he did not accept it).  It was eventually bought by some presumably wealthy people who turned it into a world class hotel.  My family visited the place in 1988.http://travel.yahoo.com/ideas/9-great-castle-hotels-in-europe.html?page=all