Michael Pollan's new book, In Defense of Food, is a good one. An NPR Science Friday interview said it so well. Probably the best, simplest summary of good, healthy eating. My summary:
Eat plants as your main dish and meat as a side dish.
Pay more for your food and eat less.
Stay away from the middle of the supermarket (processed food).
Look for "Pastured" chicken and beef. Most meat we eat were fed "junk food" (sugar and starch).
Eat how your grandmother ate.
Good choices for how you eat are also good choices for the environment (carbon footprint of processing your steak is horrendous).
Good stuff