On top of the Big Knickers and good maternity pads, get something comfy and not too tight to wear home. I had maternity leggings and a long top.
Get some non-perishable snacks, because at some point, you will be bloody starving! (I took cereal bars, etc - was a lifesaver) and plenty of water or juice. I was so thirsty afterwards and got through a whole bottle of Lime cordial in 6 hours)
For you:
Face wipes
Cooling spray
Chewing Gum for morning mouth - You will be visited by nurses and doctors before you've had a chance to brush your teeth
hairbands and brush (if your hair is long)
Plenty of change for TV card or whatever - I never watched the TV, but it was great having it there for company as I unexpectedly had a room on my own. The familiar background drone of Sky News helped me feel like I hadn't landed on another planet!
Plenty of Knickers - I can't stress this enough!
Lip Balm
Mobile phone and charger
Diary and pen for jotting down thoughts
Slippers/Flipflops - I had a pair of crocs, which although look nobbish, were great for showering in.
Comfy nursing bras and a few breast pads
Be kind to yourself and stash a bar of your favourite chocolate in your bag. I found that my mother had secretly put a bar of Snickers in my bag.. It was a fabulous surprise..
For baby:
Babygros
vests
socks/booties
mitts
hat
nappies
Simple wipes
a pramsuit/coat for going home
I never had a 'going home outfit' either. Just wrapped her up in warm layers of vest, babygrow hat mittens and pramsuit - Twas November though..
I don't know about anyone else, but on the day I was discharged, I had to wait from 9 in the morning til 6pm that evening for my drugs to arrive from pharmacy before I could go home.. That was bloody AWFUL. So make plans for an extra half a day stay.
Good Luck! How exciting for you