I've stopped using my Camelbak bladders when hiking on most Sierra Nevada trails, and use a .75 liter Camelbak bottle, with a Steripen for purifying water. Reason? There are enough water sources available to make regular re-supply quite easy, with the possible exception of the upper portions of the MW trail. A full Camelbak bladder (2 or 3 liters) weighs a lot, especially if one is trying to reduce the amount of carry weight.
Yes, sleeping with the Nalgene is a good idea, especially in full-up Winter conditions. I keep the Nalgen bottle in an ensulated sleeve and fill the bottle with warm water before retiring for the night. (The Camelbak bottles with the flip-up drinking spouts can and do leak sometimes, such as after altitude changes.) I also keep a pee-bottle in my sleeping bag, with an easily recognizable lid...for reasons that ought to be obvious...ha ha.
