Many of them are thermoelectric and are very very inefficient. Only if you are plugged in to shore power are they viable. Even the compressor ones take a fair amount of power if you are not hooked up. I guess the true wine drinkers enjoy the selection and the temperature control to be perfect. I would use the space for something more valuable to me, but then, I am far from a true wine drinker.
Also, will a subsequent owner value a wine cooler as much as you do, or will it just be a liability to the sale.
Things to think about anyway.