Tin cup is super important and overlooked. Its not enough to have 100oz camelbak if you can't put purified water in it (given you have lost or don't have any alternate means of purification than fire). I have a Ti cup but it's too narrow to nest a Nalgene bottle. I have the GSI stainless steel cup that perfectly nests a 1L Nalgene round bottle and I recently bought a Nalgene Oasis (GI canteen) which I can use my canteen cup. I am starting to prefer the Oasis as the footprint is smaller in my pack but can't add ice, harder to scrub out.

DON'T OVERLOOK THE TIN CUP. GREAT POST.