To give you an idea, off the top of my head, I would say you need to either get or at least consider:
Car seat
Pushchair
We've been lent a crib, cradle and moses basket so just bought new mattresses for them
Been lent a steriliser, so bought some bottles for it. Currently investigating breast pumps but will probably wait until once the baby arrives, however planning on an electric breast pump.
Baby bath
2 changing mats, one for downstairs, one for upstairs, plus some free travel changing mats from the sainsburys mother and baby pack, and the free boots changing bag
Couple of baby bath towels
Monitor with sensor pad
Room thermometers (get one free when you join Hipp baby club)
Plus of course baby clothes which I have no real idea how many you need but we have stacks lent or given to us!
We've also opted for
Isofix base for the car seat - makes life much easier and personally I think they're safer
Baby carrier (gone for an ergo sport one plus infant insert)
Reusable nappies (terries and shaped ones) - no chemicals, less waste, less cost. Got £50 incentive from the local council to try them so worth a go.
Reusable wipes - well if you've got the nappies, may as well use the wipes too!
Been lent an electric mobile to hang over the crib, according to my brother it's a lifesaver!
A chair bouncer thingy (picked one up second hand as it won't last past 6 months or when they work out how to roll over and flip it!).