I have used a Nalgene bottle for my water. I purchased it when I got my PUR Hiker water filter. I got the bottle because the water filter has a stopper that fits in the Nalgene bottle. This eliminates holding that while you pump water freeing up a hand. I carry 2 bottles on long trips and one for the short hike. My question is what do you use and why. I have been thinking about getting a water bladder so I wouldnt have to remove my pack to get water.