I use a Brita filter jug in the fridge.
We use Brita filter pitchers and filter all our drinking/cooking water. :) We don't buy bottled water unless we're on a trip or something (and if its a road trip, we take our Brita filters with us!). We try to be ecological and buying those individual serving bottles is really not a good idea, unless of course, it's for a group picnic or a road-trip, as I mentioned. Then we save them and re-cycle them. :P We thought, too, in the long run, it's cheaper to do the pitchers and buy new filters every 3 months, than to keep buying the bottled water all the time and having to recycle the bottles.
Now, my stepmom actually lugs her big plastic bottles (that fit in a water dispenser in her kitchen that keeps the water cold or hot) to the water store and gets her purified/filtered water that way. Since she re-uses her big jugs, she isn't wasting money or resources by buying new jugs every time she needs water, so it's quite inexpensive. She pays only for the water. And her dispenser is free now, no monthly charges, as she gets her own water and not a water company that comes to the house delivering fresh jugs of water. Of course, it costs her some electricity for the dispenser, thought, but not that much. :P
We have a water distiller.