I use VR almost all the time and my battery seems nearly endless. Hundreds, at least, of outdoor continuous mode, bracket, continuous AF - various mixtures, and the battery lasts at least days.
One thing that does seem to suck battery is leaving the camera in remote control so I can use the IR button to shoot birds outside my window without having to get up from my desk and spooking them. OTOH,I have the remote set to stay on 15 minutes, and occasionally fire a shot just to reset the timer.
But if all you're concerned about is VR, don't be. The D7k is definitely a power miser.