I drink 2-3 cups of coffee at work but I occasionally fall asleep around 4pm anyway. Probably don't get enough Zs.

Update: I'm obsessive about "good" (read top quality, arabica) coffee at work. I have a single-cup cone filter maker in my office with a Brita water filter (lots of chlorine in the water here). If only I had cold water and the time to grind the beans myself, it'd be perfect.