Lifesaver Water Purifier
Michael Pritchard at TED - video demonstrating the Lifesaver Systems water purifier. Its 0.015 micron filter eliminates all bacteria, viruses, parasites, fungi, and other microbiological waterborne pathogens. It includes a carbon filter to take out harmful minerals. It does NOT remove salt. Looks to me like something no house should be without. Purchase in the USA at HTiStore.com or at Lifesaver USA. The 4000-liter bottle costs $150. You'll likely also want spare carbon filters, pre-filters, nozzles, and a strap. $214 + $22 shipping = $236.