It should be mostly things for you to do while in labor and your own toiletries. The hospital will provide everything for the baby. However, if you want you can also pack softer blankies than they provide (should still be stretchy and thin though so you can use them for swaddling) and a diaper bag for the trip home if it's a long one. Make sure to include a "going home" outfit for baby that is season appropriate.
Also, if you plan to breastfeed and it's possible you'll be in the hospital for a few days, take a manual pump with you and some of the breastmilk storage bags made by Gerber. With my second baby my milk came in while we were still in the hospital and I was in agony. He wasn't really interested in eating much yet since he was still in the sleep cycle that they go into for the first few days after birth, and when he was interested I was too engorged to make it very easy for him. I wished I had my pump with me every minute of every day! I ended up using the hospital's, but it wasn't very helpful since I prefer manual pumps. I pumped four full feedings worth of milk the second we got home! :)
Take a Boppy pillow with you. It can go a LONG way toward making both you and baby more comfortable whether you are BFing or bottle feeding. Make sure to take extra slip-covers for it.
Take your make-up if you feel like you can't stand to have your pic taken without it.
Take sports bras instead of nursing bras. Sports bras give enough support without underwires (which can contribute to plugged ducts especially in the beginning) and sports bras will be much more comfortable for you during your stay. In fact, I've never used nursing bras. I've always been in sports bras and I've always been super comfy. It's easy to just pull it up on the side you're nursing on.
Take some t-shirts for yourself that are at least one size larger than usual and some comfy pajama pants. I was WAY more comfortable in the hospital with my own pj's.
Take your own bath robe and slippers if you want
If you've got it, take an iPod full of your favorites for labor. Also if you choose take a deck of cards, a good book, a portable DVD player with some of your favorite, engrossing movies (like Pride and Prejudice or something). Really anything that you think you could use to take your mind off of labor for a little while.
Take some non-perishable snacks for you and dad like granola bars and self-contained fruit like oranges etc.. Even if you're not allowed to eat during labor and delivery (every hospital is different it seems) you'll still have some for later. They'll only bring three meals a day in the maternity ward so you'll probably get hungry in between meals. You'll have to pack this stuff right when you go though, or have dad run out and grab it after you get checked in.
Of course, don't forget the camera and camcorder. Make sure the batteries are charged and ready to go.
Some hospitals allow moms to use a hand mirror to watch delivery. It can help motivate moms that are tired of pushing. Pack one in case your hospital allows this.
Don't forget the tennis balls so dad can give a good counter-pressure massage during bad contractions.
And if you still have room after all of that, take your favorite snuggly blanket and pillow with you for the recovery room.
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Edit: I forgot to mention your own panties and pads, but another mom remembered. This is important. The disposable stuff the hospital provides is majorly uncomfortable.
Congratulations and best of luck for a happy and healthy delivery!
