It depends on how much or little the phone is doing, doesn't it. How much of that time is it connected to wifi? How much data transferred? How many background apps are you running? Do they use location services, orientation sensors, light sensors, etc.? What size is the screen, and what is its power output?
It's true, I put it through pretty light usage, with a meg or two data over wifi a day, a few texts and calls. Still gets 2x the life of any other phone I've ever had my hands on though, no matter how light I used them.
My Nokia regularly goes a week without a charge with light usage.
(I've heard tell the power management in the Symbian kernel far outstrips the competitors, which probably explains it.)