Drink no caffine, soda dehydrates you. Your urine should be clear. Water and gatorade 50/50 all the way. What they had us doing at the burn whenever we could, just drink and drink.
Matt brings up an excellent point that's often overlooked - Urine Color!
If it's anything but crystal clear, you need to drink more, period!
In basic, we had color charts above every urinal. I went through 9 weeks of basic with clear urine. I was drinking 8-10 quarts of water per day, less on the days we had classes and hit the range.
Bottom line - you body functions best when properly hydrated. If you have to pee alot, who cares? Every time you go, you are ridding your body of waste, so get it out!
When hydrating, stay away from diuretics like caffeine. Coke, coffee, tea even chocolate can cause your body to eliminate moisture - which is bad (unless you have edema, but that's another story).