I highly recommend taking the hospital tour and asking as many questions as you can think of. Find out what they will be giving you, Then figure out what you're comfortable using. Our hospital gives an admission bag that includes mesh panties, pads, shampoo, conditioner, soap, toothbrush, toothpaste, and a comb. I am comfortable with using this stuff so didn't pack my own. They also gave me tucks, dermaplast and a peri bottle.
With my first daughter, we brought so much stuff and didn't use most of it. So since then, we pack light I have a doula, so she brings stuff for labor. For labor, I will probably bring my ipod and speaker, a sports bra and I bring a baby calendar for footprints. I wear their gown until I don't. I birth naked. I'm bringing a bra this time, just in case, but doubt I will use it. I might if I get to have a waterbirth, but I doubt it. You might try contacting DONA and see if there's a student doula who needs a birth for certification that would be willing to do your birth for free/cheap.
For baby, I pack a regular diaper like we would carry everyday. I throw in a special gown and hat that they wear while in the hospital. I have a coming home outfit. The girls all wear home what I wore home. And we use it for hospital portraits, which my mom buys. The hospital gives us diapers and wipes, blankets, etc.
For me, after birth, I pack a set of jammies, often a nursing nightgown, my boppy, an outfit to go home in, though last time I wore home what I wore in and a spare pair of panties, just in case, though I prefer the mesh ones the first week or so. I also throw in a pair of socks, though my hospital also gave me a pair of those because they wanted me to have grippy things to walk in.
For dh, he packs his toiletries, a couple outfits, a t-shirt and pajama pants, socks, underwear, etc. He is also in charge of electronics-camera, video camera, laptop, chargers, etc.
My mom brings the girls everyday and we are close enough that dh could go home if we needed something. He stays at the hospital with me the whole time, except to eat or run an errand.
I usually pack a bag a couple weeks before I'm due. I'm thinking this time, I'll have my bags ready at 34 weeks, just in case. My friends had a 34 weeker and she came home with them, no NICU, so I figure that's the soonest I would need all my bags.