I find hydration systems rather fiddley and intricate. It is way to easy for them to leak, drip, and otherwise fail. I have lots of Nalgenes, platypus containers (platypi?), and recycled gatorade/soda bottles. I prefer the wider mouths of the Gatorade varieties. I really like the way a platypus will flatten out when empty and save space.

The most important characteristic of any "hydration system" is capacity - make sure you can carry enough water for conditions. I routinely ran through more than a gallon a day in desert conditions and still produced rather dark urine. Cooler, more humid situations decrease the need for water considerably.

I much prefer boiling as a water purification technique - positive and simple. I occasionally use a Katadyn Hiker filter and it is usually worthwhile to carry Aquapure tablets as a backup.

Some of your foods are canteens in disguise. I believe an apple is something like 85% water.

Finally, don't obsess over impure water. I have partaken of some pretty nasty sources - most memorably, drinking from a high mountain pothole and spying coyote poop in the water two feet away. There were no after effects. Nothing in the water is going to do as much harm as dehydration. If you can get back to town, the blessings of medical science can cure your malady, but you must win your way to civilization first.