I keep water with me at all times, but that's because I'm a thirsty woman~!
However, I think the "absolutely must have 64oz per day" is a myth that's been busted. The original study that gave birth to the eight-glasses commandment actually found that you need to consume about 64oz. a day
from all sources, including water from food and other beverages. This figure was usually misreported as eight eight-ounce glasses of water a day.
So now we know that ALL liquid is part of the deal. Coffee, soda, juice, whatever - you even get water in the veggies & fruits you eat. Of course, the best easiest way is plain simple H2O!

But feel free to "dress it up" with lemon or lime wedges, or Crystal Light or whatever. Count your morning coffee! Count that diet soda! Count that glass of orange juice!
I drink when I'm thirsty. I drink before I eat a meal. I judge my intake by my pee color. Dark yellow means dehydration. Light yellow is good, but mine is always almost clear.