I have a cup holder mounted on my city bike, I use a 16 ounce Tervis cup with a lid on it. Refill when empty with beverage of choice. It has been known to hold the occasional margarita

I don't really worry too much about water intake, I drink water all the time, rather than other beverages. Only exception is first thing in the morning I am going to have my two cups of coffee... No Coffee, No Workee!
Aaron