I like cucumber water (generally with some lime juice), but most infusions don't do much for me because low temp extraction is just not very good: you use a lot of fruit for a pretty small effect. Cucumber is an exception (watermelon works pretty well too), and cucumber seeds in particular. In fact, splitting a cucumber (or two) and scooping the seeds out for cucumber water still leaves the rest of the cucumber for salad/salsa/whatever so you get the best of both worlds. Maybe I should try the stringy goop around the seeds of a cantaloupe.
As for other things: muddled mint does ok but if you really want to get all the flavor out you have to cook that (hard, i.e. boil not steep), at which point you're maybe technically drinking infused water but most people would call it "tea", and other fruits certainly taste good infused, but in almost all cases, you get better flavor for less fruit by mashing and/or cooking them down and adding as a concentrate/juice/syrup. Now if you are planning on eating the fruit out of your water, then go for it.
...also, alcohol does well for extraction so infusing a vodka or gin is useful, though its too bad cucumber infusions doesn't last long.