I've always been a smoothie fan, and would like to get into the habit of making my own. I have frozen mixed berries (what about when berries are in season? better to use fresh or frozen?), bananas, whey protein powder, non-fat greek yogurt, skim milk, and OJ. What are some good variations with these ingredients and what else is good in smoothies? What's a good proportion of fruit to ice to liquid etc? I'll be making either one or two servings at a time. Any recipes, techniques, and tips would be appreciated! Thanks!!!