I know this is not for everyone, but try restoring your iPhone to factory settings.
I didn't have anything THAT important on my phone, and this battery problem was driving me crazy. Some people say the bug gets backed up too, so when you restore with the latest one you'll still get the problems.
Before restoring, my last charge got 6:34 of standby and 3:47 of usage. Today it got 12:14 of standby and 7:54 of usage.
On both situations my 4S had 50% brightness, auto-brightness off, same type of use, and the screenshots were taken on 1% battery, I just don't know how to post them.
It definitely worked for me, but not everyone is willing to give their iPhone a fresh start. I just hoped the iPhone could get the same battery life my iPad 3 does someday. 3G on, sometimes using wi-fi, it's on 53% with 1 day and 15 hours of standby and 6:21 of usage! :)