the new platypus bottles are awesome for ultralight hiking and backpacking. they weigh less than an ounce, and won’t puncture, and are bpa free (and don’t leave your water tasting like plastic) AND they make it easier to drink more and stay hydrated. they don’t come with the push/pull cap, but buy them separately, they’re worth it. also, the corners on the bottom are sharp, so take a pair of scissors and round them off. it’ll save a lot of worrying about ripping your backpack.
the whole point: unlike a nalgene bottle (or any metal or plastic bottle) these don’t take up space once they’re empty. you can fold it up to the size of a thick marker, you won’t be carrying around extra weight for no reason, and you drink more water overall. a+ from me, dan, and brian.