Nourishing snacks or munchies, so that your partner does not have to leave you and rush out for sustenance. A camera just in case you want to record the most memorable day of your life. A nursing bra. A few disposable panties. Anything that may have been suggested to you in the pre-natal class.
Some hospitals allow beanbags for labour.
But do check with yours in advance. Phone numbers of important friends and relatives. Last, but not the least, coins for the telephone. A couple of spare nightgowns with a front-opening, of course. A pair of bathroom slippers and a bed jacket.