More tools to find books for readers:
This UK service connected to the public libraries in Britain allows you to pick a series of attributes (on a sliding scale) and then view a list of suggestions. (Residents of the UK can even borrow the novels from their local public library.) In some cases, you can read a snippet from the book choices.)
Series lists from Kent District Library
Links also to Amazon which allows you to read the first few pages of most books.
I've mentioned this site before. A great "visual" representation of an author and his/her realtion to the constellation of similar writers. The closer two writers are, the more likely someone will like both of them. More of an author-suggester than a book-suggester.
Iowa RA list wiki
Suggested reading lists assembled by the Iowa Librarians' Readers' Advisory Group.