My favorite combination of fruits is lots of berries with a few peaches added in.
For every 6 cups of fruit add:
1/4 cup honey
1/3 cup lime juice (or lemon juice)
1/4 cup chopped mint
Depending on how sweet your fruit is (and how big your sweet tooth is), you can add more juice or more honey to suit your preference. I use a little less honey than this calls for. Since I rarely eat anything sweet, a little goes a long way for me.