I use Platypus hydration bladder and a softsided Nalgene around camp.

My cup is a small plastic thing that doubles as a measuring cup and nests inside the pot or, if I have a protein smoothy binge for breakfasts, a small 16 oz Nalgene to shake the lumps out of it. Never gets used on the trail so whatever my cup is, it's in the bear can or the pot while hiking.

I have 32 oz Nalgenes and one of those stainless nesting cups. I take the cup and a few Esbit tabs when taking the SAR gear out for a spin, since I'm quite minimalist then. Never bother to nest it with anything tho. It's what passes for a cook pot.