Location: Steelhead country|striper coast|bonefish belt
Of course water is the only drink you can still enjoy after it's been sloshing around in the backpack all afternoon on a july day. Given one choice that would be it. I like Gatorade for hydration but it sure tastes bad warm.
Being of PNW influence I am big on venti iced americano / extra ice and no water with a splash of cream, in essence four shots of espresso over ice in a large cup. The melting ice provides just the right dilution as you drink it. Too fast or too slow and you miss the window.
In my steelheading days in the PNW I used to drink this kind of fruit nectar, can't remember the brand but it was like a natural smoothie / meal in a can. None of this thick yogurt crap or tutti fruitty kid stuff, just pure fruit 'nectar' and damn good regardless of flavor.
Ice cold water is number one. I also feel the same way about Sprecher's root beer (made just north of Milwaukee) that many of you have expressed about Henry Weinhardt's. It really is to-die for, and the diet version ain't bad either. Most of the microbreweries in Wisconsin, and there are a LOT of them, also make their own sodas, especially root beer. They are each unique and all are very good.