Water&Filters

The highest priority resource to get under your local control is water.  Humans can live for roughly three weeks without food, but will perish after three days without water.  Just as importantly, many diseases are water-borne, so sufficient access to water must ensure quality as well as quantity.  Ample, clean water is a necessity of life.

For most Americans, water for drinking and washing comes either from a municipal (town/city) water supply or from a private well.
To begin with, storing water is generally inconvenient.  Stored water takes up a great deal of space, it's heavy, and it needs to be replaced every couple of years because it goes stale over time.  But for people living in very dry areas or in cities, especially in areas prone to natural disasters such as earthquakes and hurricanes, storing water is the prudent thing to do.
I personally maintain about 40 gallons of water storage capacity, even though I have access to ample well and surface water. 
For any water jug, my basic requirements are reasonable price, solid construction (won't wear out after a few uses or split when bumped) and that it be free of BPA, a toxin present in some plastics.  "Guilty until proven innocent" is my motto when it comes to industrial chemicals with hormone-mimetic potential, and because of this, BPA should be avoided unless research proves it to be safe.

Having said that, if you need some h20 and all you have is pond water, and its WTSHTF time, then check these excellent water filters and storage systems out:

Check out the Berkey Filter and the Katadyn Filter:

A good standby for water purification is iodine pills.  Iodine crystals for disinfecting water are available as a trade product called "Polar Pure" from most of the regular backpacking supply places such as REI. It comes in a small bottle with a screened top, you fill it, shake it, and then decant a capful or two of the supersaturated solution into your water. The bottle has full instructions and also a thermometer so you know how long the water should sit before use. The cost was about $8 or so, last time I bought any. 
One little three ounce bottle can treat up to 2,000 quarts of water. I recommend that you buy one for each of your GOOD kits. Warning: The wire screen at the top of the bottle is there for a reason. Ingesting iodine crystals can be deadly!

 Polar Pure and other water purification tablets can be found here: