On my Galaxy Nexus using Juice Defender on normal settings, two Exchange accounts configured (that get e-mail all day long), a POP3 account, GMail, G+, I typically get 15-18 hours. I can push 20-21 hours if I am not looking at my phone too often.
Today, I am at just shy of 15 hours with 13% of the battery left. I have used 2 hours of screen time, over 30 minutes of CPU time for Exchange Activesync, a few voice calls using a Bluetooth speakerphone, and I listened to a playlist from Amazon MP3 Cloud Player during my 30 minute run at the gym. Most of my data usage is wireless - but wireless is fairly available most places and certainly at work.
My recommendations - use WiFi wherever possible, use Juice Defender to turn off the data radio when you aren't using it, keep you screen set to automatic brightness, and minimize use of 4G unless you absolutely need it.