just bought my Storm last night, and after the first charge and 9 hours of use its 1\2 empty and I didnt use the internet but ofr about 15 min. and 5 short phone calls and 6 text msng.
I had the same problem on my first charge. All I did was let it get really low (well...I didn't have a choice in that one actually!) and then recharge. The second time, it held the charge for nearly 3 days.
I am, however, now having the same problem 4 months later. VZ is sending me a new battery.
This is one of the most common things to come up on the storm and there are tons of things that can help with your battery life. there's actually so many suggestions i can't just post one link to sum it up.