Comfie clothes - I was sore from a c-sect and DD was born in winter. So it was trackies for me plus they were comfie to rest/sleep in during the day.
Slippers or socks- Feet got cold when getting up for night feeds
Button up shirt or nightie - easier to breast feed in
Toiletries
Hair straightener - I could get away with a few days of not washing my hair.
Maternity pads - went through alot of these. (tip: place in your clean undies before having a shower/getting changed as you tend to bleed heavily the first week and you need to put on straight away/quickly)
Pen & Paper or notebook - good for taking notes when the midwives tell you stuff b/c you can't always remember once they are gone
Camera, phone/phone charger.
Alot of the other stuff the gals have said.
I think it is better to overpack than underpack!