Mix the dry ingredients (the oats, flax meal, and chips) in a small- to medium-size bowl. In a larger bowl, combine the peanut butter, honey, and vanilla. Add the dry ingredients to the wet ingredients, and stir until thoroughly incorporated. For easier rolling, place the mixture in the refrigerator for 15-20 minutes. (You may roll them right away, but they will tend to stick to your hands at this point. If you refrigerate much longer than that, the mixture will be firmer than ideal for easy rolling.)