I really liked Librarything - have only put on a few books to look at the system but will go back and put in more later - main good aspects for me were reading reviews that other people had written - some very well written and well thought out reviews. Also looked at Librarians for Librarything and read a section on computer rage! in libraries.
A good site and will use more fully later. http://www.librarything.com/catalog/jclifftop