I all ready have the winter tank permanantly occupying a spot in my breakfast nook where its really not in the way.
I figure for the cost of heating the pond all winter, I can run the indoor tank much more efficiently and have better success at keeping the fish alive. I am not keeping koi, just pond comets, so they won't get too big for the tank or the pond. I don't drain the pond out in the fall, I just lower the water level a bit and pull out the pumps and drain the lines. The skimmer filter has a weir that can be closed off to seal the inlet, so I can drain it down for the winter. Some of the plants are native varieties that die off in the fall and remain outdoors in the winter. In the spring, I give the pond a clean out to get rid of the debris, then refill and and get it running. Once the water temp comes up, I move the fish out. It doesn't seem like too much effort, so I plan to keep on doing what works for me.