I agree with you, at least partially. I remember, in my youth while hiking in the mountains of Arizona, we were squeezing water out of some damp moss with the thought that "what we are about to drink might make us sick, but at least we will be able to get back to Tucson where we can be cured." As far as I know, I have never gotten sick from drinking bad water. But like everyone else, I have succumbed to the pervasive hype about Giardia and I often carry a filter (Pur Hiker-excellent unit!) on planned outings.

I don't bother with the tablets and stuff because, even in my minimalist gear, I have a small, light pot for boiling water - the surest way to get rid of the nasty bugs.

I learned early on that two items really crucial for survival were water and fire (we are talking about Arizona conditions here), so the basis of my survival gear has always been a canteen and redundant means of building fire. And when I say canteen, I don't mean some wimpy bag for tropical fish that the nearest cactus will immediately perforate. My most cost effective container is a Gatorade bottle, followed by Platypus containers (very light and compact, but pricey). Nalgene bottles are tough, with secure closures, but are relatively heavy.

In the country where I learned my early survival skills, the three most important factors were water, water, and water. In a tough situation today, I would prefer to treat water before consuming it, but if necessary I would guzzle it down and head for town. I think your decisions, should you be deep in the woods, with a survival period of several days before you, would incline you to devise some means of purifying your water. Boiling, which is relatively slow, really doesn't take that long. It is by far the best means for dealing with pathogens in the water, and I suppose if you were concerned about heavy metals in the water, you could even rig up a distillation unit - just be sure you have lots of fuel.