You still probably have over 20wks to go, so don't panic! You don't actually NEED very much, and shops will still be open after you've had your baby.
I think we got:
SLEEP: cotbed (eBay); rather than moses basket we used a Samsonite Pop up Travel Cot (ebay); sheets (charity shop, cut and hemmed); 2 cellular blankets, useful for swaddling/layering (John Lewis) and a Goi Goi pillow (got this after DS started to get a flat head - think they are now Lila Kuddas or something?)
CLEAN: reusable nappies, but only started to use them a bit later on (Nappy Lady shop); cloths to clean top and bottom with (didn't use top and tail bowls, just wee plastic bowls we already had); tummy tub (as I was convinced I'd want one; it was useful but not essential).
Muslins, which were great to drap over my shoulder to catch his burps... nice accessory.
WARM: think about what time of year your LO will be born. DS was born at end Aug, so we had some sleeveless body suits, some with short sleeves and some with long sleeves, plus some babygros - all bought in 0-3months size as he was 8lb 12oz when born and the Newborn sizes sometimes only go to 10lbs. Also hat, socks, scratch mits and cardi.
MILK: I breastfed, got a hand pump to express and then DS refused to take milk from a bottle. So personally I would just get a bottle or two, just in case - but as I said, shops will still be open and your OH can rush out and get stuff after the birth! I used a firm pillow to support DS when he fed, you don't have to buy a special pillow. Or chair. So long as you can sit somewhere that your back is well-supported, your arms not restricted by chair arms, and with either a good book or TV remote in reach (preferably with cup of tea or water in reach too!).
TRAVEL: if you have a car, you WILL need a car seat; you may want a pram (minefield!) but equally you could use a sling (different kind of minefield - lots to choose from!). There are whole threads on here about the merits of each...
I think that was it. You'll probably be given loads of clothes and toys, so I'd just go for the bigger stuff just now. And re toys, they really don't need anything until they are a few weeks older.
Have fun!