Don't skimp on the ability to carry lots of water, there is little else worse than not being able to get it (Did it once in the Frank Church, never again!) or taking half your day to get to it. A camelback and a nalgene bottle is about the bare minimum I would do and that's only if there is water everywhere. If you are hunting something like the east side Wilderness areas or the Frank Church, go with the ability to carry another Gallon on top of the nalgene and camelback, you don't need to have it full when you leave, just to have some back at camp so you can go a couple a days without refilling if you need to.
Another tip, the Fiji brand (large size) water bottles are stout, last for years and weigh less then most nalgene's.
