Its so easy to go overboard when prepping for the Baby's arrival(I literally couldnt stop myself buying 000 clothes!) I would say

Car seat
Pram or Sling(I used a sling until DD was about 2 months old)
Cot(She didnt go in it untill around 3 months)
Nappiesx a million!
Wipesx heaps!
Facewashersx 10 or so
Singletsx 6
Jumpsuits x 6
socksx 4
muslinsx 6

Thats about all I can think of, people love to buy for babies too so if you are having a shower you will get heaps of this stuff.
HTH