I love my slow cooker, but like EZ, I don't use a recipe book. (Actually, I don't even own any recipe books. I bet that's true of a lot of people my age - it just isn't necessary anymore.)
My favorite recipe site is Recipezaar, so until you find a book that you like, try this link: http://www.recipezaar.com/recipes.ph...%2Frecipes.php
It's a search for all things tagged both "crock pot" and "healthy," sorted with the highest rated recipes first.