For your water purification, I'd suggest you look at a
SteriPEN - it uses ultraviolet light to sterilize water. Very quick, very lightweight, very effective. The only thing that equals it in killing microbes (like Giardia, Cryptosporidium, Salmonella and E. coli) is boiling -- and who wants to wait for boiled water to cool down? There's even a solar carry case to charge the batteries.