Today will be my second full day with the Nexus. Upon receipt of it Wednesday evening, I applied an XO Skin before installing the extended battery ($25 @ a corporate store) two hours later and allowing the phone to charge overnight (~7 hours) without having ever powered it on.
The following morning at 05:50, I powered it on and proceeded to treat it like a new toy, exploring it every few minutes throughout the day on top of my normal, moderate usage (20-30 texts, several short-to-medium length phone calls, google searches, setting up apps, options, etc). I had yet to disable anything, other than changing the live wallpaper to a static image. On the drive to and from a friend's birthday party, I used navigation for ~20 minutes each way. I powered off the phone at ~23:30 and set it on the charger; it was at ~7% charge at the time.
The next morning, I powered the Nexus on at 05:45. I installed a dozen apps and a wallpaper over the course of the day, many of which involved navigating to and downloading from links on webpages via chrome-to-phone. However, the Nexus was plugged into my netbook for a total of ~15 minutes on and off while I tried to figure out how to get MTP working in linux (fail). I then spent 1:55:55 hours over 5 phone calls embroiled in a legalese battle with Sprint to finally get my ETF down to $0 (success!). At some point I read something on this forum about disabling Window/Transition animation scale, so I set those to 'off'. During the evening, I used Google Talk video chat with my wife to make sure she didn't scold me for picking up the wrong thing at the store (success!). Upon returning home, I gave her (new to smartphones) a Nexus tutorial. Later at night, I didn't not power off the phone before bed, as it was still at 16% (2:4:18 hours screen on).
Now at 24 hours, the battery is at 12% . Wifi assumes connectivity duties at home while 4G takes over whenever I'm out (28.5 Mbps+). I don't actively manage any radios, auto-brightness is on, and the syncing options for Google+, email, and the rest are currently default (I don't have a facebook account). I am certain that once my 'new toy' syndrome calms down, I'll be getting in excess of 30 hours to a charge. It's not quite my old Nokia candybar which would go on week-long power fasts, but I'm pleased with the substantial improvement over my HTC Evo 4G.
Edit: The wife's Nexus was at 32 hours and 13% when she turned it off for the purpose of charging this morning.
Edit: I'm not rooted.