Hmmmm... we have a lot of stuff for baby still, but a lot that also needs to be replaced or that I got rid of knowing we'd need new...
Things I will need to/want to buy...
1) a *new* car seat (I never buy a carseat second hand)
2) a crib (most likely also new because of safety issues)
3) some more flats. I like them as an extra pad for the change table, burp clothes, spill pads and the odd time diapers
4) some new nursing tanks, mine are all worn out and they are my favorite thing
5) possibly a bassinet, we left our old one and *I* am a horrible co sleeper. I like my space, even from DH
6) bouncy chair(s). Yes plural. I like having one in the bathroom and one on each floor in the main living space. I think I have two or three and I may get one more second hand. I hate having to move them and they are essential items to me, when I need a safe place to rest my arms, go to the bathroom, have a shower.
7) lots of diapers and wipes of whatever flavor you are using
8) a change pad. We used a change table with our first and with our second just changed her on our bed. But I would make the bed each day and just set up a little "changing station" on the bed. This time I have a change table from when I was doing daycare so I'm going to paint it and put it in the nursery
9) for me a good stroller is key. I love my BOB. I love my carriers too but I can't carry full time with my fibromyalgia, so I love a really really good stroller (I also like to have a small but heavier duty umbrella type stroller $60-100 not the $5-20 ones, for the times you possibly need a stroller but don't want to lug a bigger one around. I call it my hospital stroller and I still take it if my older kids are sick. )
10) I want an Ergo this time. I have many meitai's which I love but I think the Ergo may be better for me when they get bigger.
11) a chest of drawers, although this could be combined or low enough be used as a change table
12) i will also get a high chair that straps onto a chair as my old one is just too big for our kitchen
That's about it. I do have an electric breast pump (not too expensive a model) for the odd time I'm going out longer than a couple hours, although my babies hate bottles so the couple times I went out before they were on solids I would leave a bottle, a sippy cup, a regular cup and a spoon for the person watching them and they always figured out what worked best for both of them