I was wondering about the car seat thing too, but nobody ever actually checked- they just asked me if we had one (both times I was bringing a baby home, 2 different hospitals)
baby needs comfy warm soft things. Just bring sleepers and little vests - don't bother with anything that doesn't open from the bottom- ie, stuff that you'd have to take right off to change the nappies- also try to bring the ones with "feet" in them, so you don't need the socks ( I have never seen a sock that will stay on a nweborn foot for more than 10 seconds!!)
new babies .H.A.T,e getting changed- you want to be as quick as possible.Anything with fiddly bits, buttons, or stuff that you have to do up at the back are a no-no.
Cooton wool balls are better than wipes for the firt few days (weeks) just dip in plain warm water and clan baby's bum. You will need a packet of the cotton balls anyway- for cleaning baby's eye's etc.
You won't need talc. Most hospitals like you to bring your own bottles and formula, if you plan to bottle feed, but they probabkly wont let your baby go hungry if you forget. It's really great if you can breastfeed for the first few days (not to mention less packing) but you need to do whatever you are comfortable with.
15 nappies will probably last about 2 days. Bring a few extra.
Alot of newborn babies like to wear a little hat, because they lose a lot of heat from their heads. You might like to bring one in case your baby likes it.
Good luck!!!