Unless you can find good-quality fresh fruit, it is better to use canned. For the melon, I've used honeydew, canteloupe, and casaba with good results. Watermelon is interesting, but has a very diferent texture from the others. More important than the actual variety is that it is ripe. Unfortunately, New York supermarkets only seem to sell the kind of melon that goes from rock-hard to rotten without passing through ripe.
Bananas are best when they are just starting to get brown speckles.
My mother uses orange juice for the liquid, but I prefer nectar. The combination of the prune and cherry syrups give it a nice color. Sometimes I add a bit of lemon juice for tartness. I've experimented with cherry liqueur, but didn't really like the results. Use whatever fruit you find fresh in the market.