Here's the thread rockinrobin mentioned:
http://www.3fatchicks.com/forum/showthread.php?t=99663
My take on it is that it we NEED hydration, and water is an excellent way to stay hydrated (but not the only way). But how much water we need (as water only) may not be as much as we've heard. There doesn't seem to be research evidence that we need even 64 ounces of pure water per day. Here's the article I linked to on the other thread regarding that point:
http://ajpregu.physiology.org/cgi/co...ull/283/5/R993
That being said, it's hard to drink too much water. If you like it and it helps you on a daily basis -- drink! And be sure to drink following workouts and in the heat. It IS important to be hydrated.
But, if you're like me and don't drink that much actual water, take heart. If you drink fluids (not just coffee) and eat lots of fruits and veggies (and soup, etc) you're probably getting enough.
Again, my opinion...