Same here with the stock battery. I bought one of those nop name Chinese 1800mah ones. Which should have given me another hour or so. I ended up with almost 3x longer life. I can go all day, then leave if on my desk, then be at 30% battery in the morning. The stock battery, 6 hours. I was always near a charger. USB or wall.
Evo is Evil, and I love it
I have the Seidio 1750 mAh battery as a back up and after a month of switching back and forth between the stock and Seidio my battery life is almost identical. No two days are exactly the same so from my test my life was almost spot on between the stock 1500 and the after market 1750....
But I average 16 hours on a single charge and still have about 20 - 40% remaining depending on my use for that day...