Water, water, water, Gatorade, water , water, water. Water is great but somehow you need to get some salts and sugars back in the body that you lose through sweating. Soda, beer although soooooo very good on a hot day are Terrible for you. Remember, if you feel thirsty you are already dehydrated and behind the 8 ball.
In the summer time when I'm at the firehouse you will rarely see me without a water bottle within arms reach. When the bell hits and it'sin the 90's and 80% humidity that is not the time to start drinking. Same with working in the heat or riding. Get hydrated before and stay that way.