you can go wild on smoothies any way you can. I love them and make them daily during the summer or when I come back from sports in the evening. I either use yoghurt and sweetener or fresh orange juice and throw in melon or kiwi or strawberries or kiwi.
There is a reason why two people stay together: they give eachother something nobody else can !
You can even use soft tofu for smoothies. I've blended just about anything I could, added in some ground flax seeds and topped with wheat germ. Cherries are marvelous, any citrus is good (except maybe kumquats).
Given that we are about to go into fresh fruit season, just buy what you enjoy fresh from farm stands, blenderize it right away, then pour into ice cube trays. When they're frozen, just pop them into a plastic bag. When you want a smoothie of that particular flavor, just grab a couple of cubes and let 'er rip!
You'll know you've created God in your own image when He hates all the people you do.