I had a battery life problem a few days after getting the phone - turned off the NFC - which worked for couple weeks. As I started to get more Apps - specifically those with background task functionality - the battery life started to tank again - barely 10 hours with light usage.
I remembered how with my Android tablet which allows apps to multi-task, some apps simply guzzled battery life. So, I blocked the background running rights for all the apps - battery life shot up dramatically - now get 2-3 days with light usage!
Tried enabling background task rights to just the apps I care about (Amazing Weather HD, Weave News Reader, and WPCentral) - and still have excellent battery life. Apps I disabled - Evernote, Facebook, Groupon, LinkedIn, Nokia Drive+ Beta. I have not tested enabling these one at a time to figure out which one (or more) is causing the battery drain in the background.
To clarify - I'm not talking about uninstalling the apps. Simply disable background task rights via Settings -> applications -> background tasks -> block each app.
My guess is that some apps are either programmed poorly in terms of how much processing they use in the background or there is a bug in the OS which only affects certain apps.
Point - try turning off background task access for all apps for a day or two. Gradually turn on the apps which you care about their background task functionality to try to pin point which apps are the problem.