I found a few things completely invaluable
1.) a sports bottle for drinking my water out of - you can hold it anyway up and it doesn't spill when you accidentally kick it over.
2.) a selection of different sized baby grows, dd didn't fit newborn.
3.) some of those tablets you use for making sports drinks - kept me going for 23 hours of labour
4.) flip flops for going to the shower
5.) Breast feeding pillow - great for sorting out dd's latch and a great spare pillow.
6.) lots of snacks (dd was born just after halloween - so we had lots left over) DP was very grateful as he was stuck in the labour ward with me for the entire labour.
7.) a private room, I was in for 7 days in total, and watching the other mums leave to go home while I was stuck on the public ward was depressing.
8.) get your birth partner to pack your bag - I nagged DP to do it for weeks and eventually did it myself, I wanted to throttle him when he kept asking where X was.