Oooh good thread, my two hospital bags were fantastic, shame I never got to open the labour bag! This was because it all went quicker than expected but the things I packed could be good for someone else:
Labour bag:
Delivery clothes eg long t-shirt or old nightie.
Bottled water/carton drinks
Flannels
Wet Ones
Glucose tablets
Hand mirror (for watching the baby's head come out! I couldn't have used one if I tried)
Hair band (you sweat and it gets everywhere)
Camera/film (I packed several disposable cameras)
Stuff for afterwards such as: maternity pads, clean undies, change of clothes, dressing gown, outfit for baby, toiletries, etc
Lip balm (your lips get dry and sore)
Ward bag:
Pants - lots of them! I bought cheap big black knickers because they are more substantial and comfy than disposable pants, however I used both at the same time for several days.
Maternity pads - estimate what you think you might need, then multiply it by ten. I used maternity pads and ordinary supersize sanitary towels, ones with wings help.
Baby stuff - check with your midwife what the hospital provides, you will almost definitely need nappies, your baby won't need bath toiletries for his/her first bath so don't bother with bubblebath etc. Bring a few outfits, better to have more than you need.
Munchies for the ward, sweets and drinks etc. Hospitals are hot and breastfeeding is thirsty work!
Change for the phone (remember mobiles not allowed).
Comfy clothes - again, I bought big, cheap tracksuits and t-shirts, other mums on my ward were in nighties, some in shorts.
Don't forget essentials like hairbrush etc, I bought everything cheap and packed it all in advance so I didn't have to rush round at the last minute trying to remember to take my toothpaste. I still forgot hair conditioner though!
Lavender oil (in bath water) and arnica are good for healing afterwards.
Birth announcement cards and stamps (if you're on your own or have to stay in for a while it can kill a few hours to write them).
A good book (sounds silly but I read a lot during my 3 days in hospital; I was induced so read while I was waiting for things to kick off, also newborns often sleep loads for the first couple of days so it gives you something to do).
Dark towels (don't underestimate you blood loss!)
PS Although the hospital should give you one if you ask, a water jug is so handy for pouring warm water over your bits while you wee. Whether you tear or not you will likely be sore and ths can be really soothing.