You don't have to wear a night gown. As soon as I was allowed to take a shower I changed from the hospital gown to PJ bottoms and a T-shirt. The list the other poster listed is a good one. Also chargers for phones/cameras. Who ever will be staying with you may want a few clean outfits as well.
Doesn't really matter, whatever you are most comfortable in
I thought you had to wear a nightdress and not pjamas, thanks I will write all this down
Couple pair of pyjamas, underwear, bras, socks, bathrobe, outfit to go home in, slippers, toiltries (tooth brush, tooth paste, shampoo and conditioner), hair brush and hair ties, breast pads and actual pads... Pack something you enjoy like a book or earphones to listen to music I also have thongs for the shower (thongs as in sandals or whatever you call them where you are from... Flip flops? I don't know haha!) and make sure you have your ID and all that with you and baby car seat ready in the car.... That's what I have for my list