Zero. For this year at least.
Surely fast lenses are used to keep the shutter speed up for moving targets. In which case you don't need VR. If the subject is still, use a tripod. Even at 70mm you should be able to hand-hold at 1/60. Teles are a different story.
Or maybe get a Sony which stabilises everything
but VR is also very useful for video.
Here, let Lok expwain in this wideo: [love Lok really, much prefer him to Kai as he's much more friendly, not obnoxious like Kai]
http://youtu.be/8gHxZh7kjic?t=42s