In every group of travellers, there are a few brave souls who ignore most of the safety warnings about visiting developing countries. Forget about pesky inoculations and bottled water -- they want to really experience the culture. Usually, they survive. The last time I travelled through a rural area of a foreign country, I enjoyed the scenery while eating Pop Tarts, drinking cans of Coke, and declining most offers of local cuisine. I like to travel (really), but I have a vulnerable stomach.
This Miox Water Purifier by Mountain Safety Research would be a handy companion for my next trip. It's very portable and lightweight (I can stick it in my knapsack or purse), and promises to inactivate all bacteria, viruses, Giardia, and Cryptosporidium. What's more, it requires no pumping or iodine, and can process large volumes of water.
Sells for $129.95 on MSR's website, and also seems to be widely available in retail stores that carry outdoor gear.