I am on average pulling anywhere between 10-14 hours of battery a day on my nexus s. NOw this is with light usage during the day, and moderate usage at night.
During the day i might have a few calls and a few texts and check the forums here and facebook.
At night, lots of text's, at least double the phone calls. More forum lurking (lol), facebook, Google+, Google Music, and maybe a game or two to kill time.
The way i got my settings.
Wifi turned off when im not at home, turned on when i am at home.
Background Data is turned on.
Display brightness i have auto turned off and it set at about 35-40%, more then enough for me.
Only to show some of the screen animations.
I have Back up my data and automatic resotre set to on.
GPS turned off.
Vibration for typing on the keyboard turned off.
Everything else is pretty much stock and i get through the day fine for the most part. Some days are worse then others depending on how much i get to play with it.