I use two containers. For my usual Ohio Valley hiking trails, water sources are about 3 miles apart. Since I can drink filtered water immediately, I drink my fill of nice, cool water at each source. Between sources, I carry a full quart of water in a collapsible Nalgene Cantene. (I've used poly or lexan Nalgene bottles in the past.) I like the Cantene because it's light, but I missed the measuring marks the poly or lexan bottles had, so I marked the Cantene at 12 oz. (the amount I need to cook my evening meal.)

I also carry a two-quart MSR Dromlite bladder for those times when the water sources are farther apart, or when I want to carry extra water to a "dry" camp. (I cook very simply, eat uncooked breakfast, and don't make cocoa or coffee, so three quarts will get me from the last source in the afternoon to the first source next morning.) The Dromlite also makes a dandy pillow, filled with water or inflated with air.

Both containers were chosen because they mate with the MSR filters (Miniworks and Hyperflow) to provide a very stable unit when filtering. Before I used filters, I also had good luck with Platypus containers.