If you look at the brochure of any lens manufacturer, you will easily come across these VR (term used by Nikon) or IS (term used by Canon) lenses which seem to be similar to their counterparts without the VR/IS but are quite highly priced. For example, the Canon EF70-300mm f/4-5.6 IS USM is an IS lens as compared to the Canon EF75-300mm f/4-5.6 III. You can view these here. These are priced at INR 38,990 and INR 11,595 respectively. Though they don't have the exact same zoom range and USM is another differentiating feature between these lenses, I just used these near-siblings to exhibit the presence of lenses with/without IS.
What is VR/IS?
VR stands for vibration reduction and is the term used by Nikon. Its competitor Canon uses the term IS which stands for Image Stabilization. In either of these technologies, the underlying funda is simple - the lens mechanics detect the movement or the camera holder (the person who is using the camera) and compensates to a small extent for the movement/shake/vibration. Specifically, it compensates for pan and tilt of the camera. IS/VR features do not compensate for blur cause by the subject i.e. a fast moving car or a pouncing cheetah :)
So what's the big deal?
It is difficult for us to keep our hands absolutely steady while clicking a pic, especially when we are poised in unusual poses as we attempt to get that hatke angle. VR/IS is also useful when the lighting is not sufficient. It lets you slow the shutter speed by an additional 1 or 2 stops and yet achieve the same level of blur that you would have obtained in case of a non-IS/VR lens at a higher shutter speed. So you can slow down the shutter speed to 40 to let in more light and make the picture brighter, while still achieving the camera-holder induced blur-levels of a shutter speed of 60.
Should you pay the extra amount for a VR/IS lens?
I would suggest that you do. It's usually a small percentage over the price of the non-VR/IS lens but I personally believe that it's money rightly spent.