What baby needs:
Something to wear (layers are good so vests, onesies, footed sleepsuits, coat to go on top, hats. You don't know yet what size your baby will be (one of mine went straight into 0-3 months, one went into newborn and one I had to go out and buy "early baby" sizes) so best just to buy a few newborn and a few 0-3 month, then stock up when you know what fits. Or just get a big mixed-sizes bundle on eBay)
Something to sleep in (some or all of cot, moses basket, one of those bouncy hammock things, co-sleeper attachment, parental bed with well-trained and responsible parents. And blankets or baby sleeping bag)
Something to poo and wee in (nappies (disposable or reusable) unless you are going hardcore on Elimination Communication. Changing mat not essential but a good idea. Changing bag not essential but give thought to how you are going to transport changing supplies around in regular bag if you aren't getting one)
Something to be transported in (some or all of sling, buggy, carseat)
Milk and something to drink it out of (this may be breasts in which case less shopping is required)
Some means of being cleaned (wipes, flannel, cotton wool, baby bath if you want (although the kitchen sink is a time-honoured alternative)
Sudocrem This will become your new best friend right up until your baby is a toddler and smears a pot of it all over the front of your flat screen television.
What you need:
Maternity pads They are bigger and softer than even the most absorbant regular pads, and you will appreciate bigger and softer.
Enormous knickers
(if you're breastfeeding) nursing bras (not essential but very helpful)
Cushions (help to support baby when feeding). And Lanisoh (I never actually needed it, but if you do you will want it on hand).
Muslin cloths. Impossible to have too many.
And get an ear thermometer because they are very useful.