Prior to mid-December I hade excellent battery life: never less than 24 hours combined usage and standby. Then overnight it dropped to 8-10 hours maximum. Through these forums I found that something was wrong other than the battery where my usage and standby time was always the same (or within a few minutes of each other).
Something was causing the phone to work all the time. I tried pretty much every solution offered up on this forum and others: soft reset, hard reset, full reset with setup as new phone, all push settings off, all notifications off, all GPS settings off, all email apps removed, all non-apple apps removed...nothing made a difference.
Finally I made an appointment and went to the Apple store: Trip 1: they said it was likely the settings and changed them - no change. Trip 2: they swapped the battery - no change. Trip 3: they offered up a new phone on a warranty swap - FIXED!
Today after 8.5 hours of standby and 30 minutes of use my battery is still at 98%. Yesterday at this time is showed 8.5 hours of standby, 8 hours of use and 20% battery life.
If you are having the issue where your usage and standby times are the same, thus draining your battery very quickly, and your phone is still under warranty, I would recomment you just give in and go to Apple.
Make sure you have evidence of the issue - screen shots saved and the current status showing the same times. Make sure your have tried all of the other options suggested here and that your phone is set as such (location services off, etc.). Be sure you tell them that you have an issue with your phone usage time which is causing the battery to drain, not necessarily a problem with your battery. Show them the current status and the previous screen shots and explain to them what you've done in attempt to resolve.
I am so happy I can use my phone again without worry of running out of juice! Good luck all!