Benefits of Eggs
One egg has about 70-80 calories and is relatively low in fat and only have about 1.5 grams of saturated fat. Egg whites are a great source of protein. The egg yolk has an ample supply of nutrients and are a great source of iron(essential energy booster), lutein(protects your eyes and your heart), choline(important for proper functioning of the liver and helps metabolize fat and protein), and vitamins A, D, E and K. Some eggs contain omega 3 fatty acids as well. Egg yolks do contain cholesterol but the cholesterol from eggs doesn't have as much impact as the full fat dairy products like milk and beef which are very high in saturated fat which leads to high cholesterol.
The US department of Agriculture sets the standards and grades for eggs. Double A eggs(AA) have thicker and more firm egg whites than single A eggs(A). Brown eggs are no more less nutritious for you than white eggs. The color of the eggs is determined by the breed of chicken that lays the egg. You should use "pasteurized" eggs in recipes that call for raw eggs because the eggs have already been heated to temperatures that destroy potentially harmful bacteria. If you're concerned about the welfare of the animal then you should buy "organic". Organic means that the animal has not been uncaged and has been eating organic feed free of antibiotics, pesticides and animal bi-products.
I like to buy organic eggs that also contain DHA, an omega 3 fatty acid. Always refrigerate store bought eggs and use them within 2-3 weeks. One of my favorite snacks is to eat a hard boiled egg with either salt and pepper or some kind of hot sauce.