One thing you might want to consider is bottle weight. IIRC the weights of various 1liter bottles/containers empty are:
Guyot designs steel 1liter ~13 ozs, nalgene std wide mouth
Klean Kanteen steel 40oz ~11 ozs, weird semi-wide mouth
Nalgene polycarbonate ~5 ozs, nalgene std wide
Reused water bottle PETG ~2 ozs, small 28mm mouth
Platypus water bag <2 ozs, small 28mm mouth
That's with no water, 1 liter weighs 1 kg or about 2.2 pounds, so some of these bottles are a significant fraction of the water weight. The nalgenes are pretty bombproof and the stainless ones you can boil water safely in, so you could do without a pot.
Now for day-to-day use i carry a reused water bottle with a spare platypus. For camping, i frequently also take a nalgene, they are bulletproof and are good for mixing gatorade.
An advantage to using narrow mouth bottles is that they couple to this thing:
http://www.aquamira.com/preparedness/frontier-pro-filter-system/which allows filtering straight from the bottle, or by gravity, so you don't have to carry around a heavy pump and work it streamside.