Congratulations, KJ!! Can't wait to see pics!!
JP-- I think it really does depend on the hospital, but I think most in the US will provide everything for baby while you're in-- diapers and wipes and formula if you use it, and huge pads for you. Even clothes for the baby to wear while you're there-- A L&D nurse I know said they actually prefer for moms not to dress the baby in clothes from home until they're being discharged because then they can recognize their babies (the ones that belong there in the ward as opposed to visiting babies) at a glance.
I don't know how many babies actually visit... but that's what she said.
I don't wear nightgowns either... but I just wore a hospital gown while I was in. I put pants and a t-shirt on when I was going home, but I would not have wanted to put pants on before that. I did have a c-section, but I'm not sure how much difference that would have made. I think a nightie would be more comfy postpartum no matter how you get the baby out.