Depending on the trip, I will take plastic or stainless, or both. Wax coated leather sounds cool, but look at this one that is coated with latex: http://www.backcountrygear.com/leather-bota-bag.html#.U2FIE6fZv6p
I have no idea if latex is neutral. Wax? I guess it would depend on the wax. Wax from honeybees is probably ok. Petroleum based wax is probably not.

While I did get the platypus softbottle (actually, I neglected to see it was only a half liter... sorry if I led you on a wild goose chase), I also got two wide mouth stainless steel water bottles (one stanley, one gaiam that's painted on the outside). I found a 13" long bamboo spoon. I ordered some wire on ebay for less than $2, which I will use to make a handle to pick up the stainless steel water bottles from the fire (saw that in another post). What cooking do you think I would still need a pot for?