Okay, here's the site that everyone should be going to:
The World's Healthiest Foods
And then when you're done exploring this great site, buy the book which is about the size and weight of the Cleveland Yellow Pages. I saw it today during a playdate at "B's" house and witnessed its hugeiosity and found out that, get this, it is not organized a-z foods but by which foods are most nutritionally dense. Can you dig it? So things like mushrooms and olives come before things like rutabagas and carrots. It also has a groovy section on what "organic" means for fruits and vegetables as well as for meat.