I use the standard 2.5 gallon water dispensers that you purchase filled with distilled water.
I have 3 loaded with water at any given time. I cut a little square otu of the top of each one in order to aid in filling.
The main reason I like this containers, is because the water dispenser device is EXTREMELY HANDY. when refilling my tank after a water change, I ussually just let it go to a slow trickle, back into the aquarium. It allows the temperature to have a gradual transition, and gives a nice amount of aeration, and the fish all seem to love getting a "shower" to bathe in, with all the little bubbles that come from it.
My trick is to just add my dechlorinator (TetraSafe), 18 drips to the container, then fill it with tap water. I do this with all 3 containers, and let them sit for about 3 or 4 days.
I don't really know why I do this, but in my head I feel that the chlorine will get a better chance to completely dissolve away. So far the fish enjoy it, and my tank chemistry is AWESOME.