True Nalgene bottles come in various compositions. The ones I like the best are the 'smoke gray' color....they are capable of holding boiling water. In a survival situation that is obviously a good thing. After you've boiled it, you could pour it directly into the bottle without having to wait for it to cool. That would give you a type of 'heat pack' that you could use for some type of warming (ie. sleeping bag....) as well as allow you to continue to boiling water right away. (Assuming you only have the one container to boil in) Some water filters also fit onto some Nalgene bottles directly so you don't risk spilling water. One word of caution though when putting boiling water into it...I had to sterilize one one day so I could mix some baby formula. I had a moment of stupidity hit me when I capped the bottle and shook it to "really get it clean" and then opened it. I had it tilted with the opening down to allow it to drain into the sink.....not thinking about the pressure build up. Scalding water sprayed onto my chest and abdomen. Fortunately no one else (wife and kids near me) got hurt by my moment of stupidity.

They also clean easily.....dishwasher.

Campmor also sells a stainless steel cup that nests on the bottom (like the canteen cup does with the canteen). Saves space and has something to boil water in.