If this has been discussed already I missed it...but, is anyone familiar with the LifeStraw water filter?
Supposed to be durable, 1000 liters @ .2 microns over a 3 yr life span, under 2 oz., $19.95.
Has been used in Africa for a few years now, seems to work OK. Several YouTube videos.
http://eartheasy.com/checkout/cart/