Car seat, nappies, clothes, boobs and arms :P
Lol! Chloe, so right there. I didn't need, nor did I expect to need, bottles or formula at all for any of my four kids as they were BFed, so why would I waste money on them?

Most things I found invaluable with one baby, I didn't even use with another. I think the most useful things are things I bought after baby was born when I could tell what I needed (eg a sling instead of a humungous pram!)