As this topic was discussing the battery life of the iPhone 5, I, too, had abysmal battery life until a) I turned off Safari sync in iCloud, b) I restored settings, and c) I turned off LTE at home. My battery is currently at 22% and I unplugged it on Wednesday morning at 5:30am (as of the writing of this post, it is 11:55pm on Friday).
I'm wildly impressed. This is my first iPhone (I have had crackberries and android devices) and this is the first time I've ever gone more than 12 hours on a single charge. True, my phone has been on standby for a good portion of that time frame listed above, but I've still had a good 6.5 hours of usage (surfing the web, listening to music, minor texting, about 20 minutes actually speaking on the phone).
Note: before I fixed the settings, I was getting maybe 8 hours total (standby or otherwise) on a single charge. Right now I'm at 42.5 hours. Wow. Just... wow.