I got 6 and half hours today.... here's my stats:
Cell Standby-44%
Phone Idle-26%
Display-18%
Android OS-9%
Browser-2%
Wi-Fi-2%
I think the wifi was me just getting home and downloading a few things...but 6 hours was awful. But it actually isn't that bad, because my school has terrible reception...I watched it through my first class, I lost 20% from just that one room. It kept swapping back and forth between no bars of 4G and no bars of 3G, searching for a signal. That absolutely killed the battery...so I switched off my live wallpaper, started Juice Defender, got advanced task killer (and used it sparingly), turned the brightness down, turned off the GPS, and just went on through playing for the rest of the day. I used it heavily through my third class, I played a few games, let people play with it (Camera, 4G, etc. I let one friend check out how well the 4G was [on one bar too] and he checked his NFL Fantasy football team real quick. Quick and speedy, like it should be) and helped my friend type out an essay he had forgotten to type the night before. It lasted pretty well up until my fourth class (teacher's assistant), I walked into it with 30% battery left...and left early to go to lunch (me and the other TA were distracting the class...go figure) with about 20% left. I played music in the car, 4G still on. I finally switched off 4G at the restaurant, and it went down to 5% by the end of lunch. My fifth class I had it turned off, but turned it on once to show my friend (who is jealous because he had bought the Incredible 2) and he let me use his charger for a good 10 minutes (I hate that it doesn't show me the actual percentage, it was "still" at 5%). Turned it on one more time to take a funny picture, and it stayed off until I went home and played music in the car again.
I got it home before it died

and just installing some other stuff, and I'll be testing it tomorrow when I don't have school and I'm on WiFi at home all day (well unless I go somewhere obviously, but I'll take my charger just in case. Which is also something I'm going to be doing at school...I can always charge it during my fourth, fifth, and sixth classes. And I'm buying a car charger) and monday I'll try it out with juice defender on all day, and it set to stop all data when the screen is off.
All in all, this thing has pretty nice battery life for a 4G device. I don't plan on having to actually turn off the 4G very often if I keep Juice Defender on (and I'm thinking of purchasing the pro version too) and keep my brightness down a little. My only problem I'm going to have with battery life is that 4G is new in my town, and there is never any reception at school, I think they purposely do that.