Better Homes and Gardens New Dieter's Cookbook
This book is full of fabulous recipes with pictures.  Just about everything in here has been a hit with my family

Chris Carmichael's Fitness Cookbook by Chris Carmichael w/Jim Rutberg
Chris Carmichael was Lance Armstrong's coach.  Carmichael Training Sytems has a great view on nutrition.  Their whole philosophy is that you need calories to exist.  It is up to you what carrier you ingest for those calories.  You can use a motor yacht, a row boat, or a garbage barge.  Their whole emphasis is on whole natural foods.  I really don't think that you can go wrong with their approach.  It is practical, completely healthy and scientifically backed up with tons of research and practical use. These guys also have a really good nutrition newsletter that is emailed out periodically that I really enjoy.  I will probably post a link to it under My Favorite Articles.

The South Beach Diet and South Beach Diet Cookbook by Arthur Agatson M.D.
I found this approach to losing weight extremely difficult to stick to.  It is tough.  I need carbs and this is a very low carb/high protein diet with very low calories.  There have been a couple of studies, however, that have shown that this kind of diet can be effective for women with type II diabetes.  Personally, I take the recipes in the book and apply them into a more balanced diet.  They do have some really good things in there to try.

The Abs Diet by David Zinczenko
This one has an interesting approach to diet similar to Carmichael Training System's.  They subscribe to the idea that you need good, wholesome, real food on which to live.  I totally agree with that.  I would, however, like to see more recipes included and some of their claims backed up by real science.