Water

I should be drinking half my body weight in ounces...that's about 115 ounces of water or 14 8- ounce glasses. But I just went on this site and they told me (based on my weight and the hot climate I live in and other things) that I should be drinking 139 ounces of water, or 4 liters a day. Basically a gallon. Here's the site, it's pretty cool:

http://nutrition.about.com/library/blwatercalculator.htm