Some things I've done to achieve an 8-10 hour charge with casual usage
Instructions for this can easily be found on Google. Most of it is on the xda forums
First, you have to update to the 219 version
The update improves battery life
Second, root that sucker using motofail
Third, debloat, you can find a list of safe to FREEZE apps on xda
You can do this with root uninstall er pro
Turn off all location services
Something I noticed was that when I organized my apps in the app drawer by frequency of use, was that maps, latitude, social places and navigation were always at the top of the list, but never appeared in the battery usage. I use Pandora and the browser FAR more than anything else and they were always below them.
So I froze maps, and since the others are tied into maps, they went with it.
Another thing I did was froze my images, my files, and my music.
These are additional apps that motorola installs and seem to use the network for some reason.
I then installed a market file browser and image viewer that uses far fewer resources.
And use Google play music which is already on the phone
Remember, freeze the apps
Don't uninstall them, you'll need to unfreeze them to install ota updates and patches
And you'll need them when ice cream sandwich comes out too
Edit: I worked 9 hour shift tonight, listening to Pandora on 4g from start to finish. Had 20% remaining
The 8-10 hour guess at the beginning of this post was just that, a guess. Now I estimate I could easily get much more with casual use.