I'll have to second Kelly's response. Except I can't be that dramatic.. I've never run out of power from a good battery (my original D-reb battery failed after around two years, to the point where it would struggle to take maybe 100 shots), but I can't say I've ever used as much power as Kelly's description. I have no IS lenses, I don't use the review function, and I rarely use the color LCD at all.
I looked through my archives, and in general the most I've found for a day is around 500 shots. So I haven't come close. I know a single battery is supposed to be good for a thousand or more, although I don't know whether that was with or without LCD review and such.