Is it better to eat an apple with skin or without? The numbers don't lie. The ORAC value above is a measure of the apple's antioxidants and for those with skin (an average across all varieties) the number is 3,049. For the same measurement (all varieties) but without their skin on, the number drops to 2,573. That means by eating an apple with the skin kept on, you are getting 18% higher antioxidant content.
When eating apples with the skin, buying organic is even more important. Why? Because much of the pesticide and herbicide residue is found on the skin. Though it should be noted that even if you peeled it completely, those chemicals still get absorbed into the fruit. Paying more for organic isn't always worth it but this is one piece of produce where the added cost makes sense.
USDA Database for the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 - Prepared by Nutrient Data Laboratory, Beltsville Human Nutrition Research Center (BHNRC), Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA) - May 2010