I do. My philosophy is why have fast data if you don't use it. I know people who turn off 3G on their smart phones and turn off mobile data and background syncing to save battery. But when you do that, you have no smart phone so I don't get it.
I would never recommend turning off data altogether to save battery, if you are going to do that, buy a dumb phone.

). I know you like sense (not for me, but its a personal preference
) so maybe HTC will see the success of the MAXX and come out with something similar (high spec'd phone with a honking battery). Engadget did a battery test with the maxx looping a video stream and it took 16hrs to kill it
. Let me poke around some top end phone forums and the interwebs, see if I can't give you some pros and cons for devices available now and maybe coming soon for VZW. Your phone shouldn't be as hard as installing a stereo