This is a great start, but I like to punch up the nutritional value with fresh aloe vera. See http://www.naturalnews.com/021858.html for the myriad reasons why you definitely want aloe vera in your smoothies. http://www.naturalnews.com/PhotoTour_Aloe_Vera_1.html shows you how to harvest the aloe gel.
Here's a few more changes I would make: swap an avocado for one of the bananas to get more beneficial oils; a teaspoon of coconut oil would also be great. Add organic parsley and cilantro for detoxifying properties, and organic spinach for additional vitamins, minerals, and flavor. A few spoons of organic blueberries will add both sweetness and antioxidants (the organic really has twice the flavor, and thus nutrition, over the non-organic!). Sprinkle in some cinnamon for blood sugar control and flavor, add some xylitol for sweetness and to ward off cavity-causing bacteria, and a spoon of brewer's yeast (I like non-GMO products from Lewis Labs or Bluebonnet) for more B vitamins. If you have other green superfood powders like Vitamineral Green from www.healthforce.com or Pure Synergy from www.thesynergycompany.com, add a spoon or two of that as well because those products have such a wide array of high quality greens and enzymes that you are not likely to source individually. Make sure the orange juice is fresh squeezed, as the pasteurized stuff is probably more poison than beneficial. The end product may not be quite as green looking, but the nutritional value will be extremely high!