Congratulations.
We have the Chicco cortina keyfit30 system -it was first in safety on consumer reports - it's fine, just the carseat is a bit heavy. We have an extra carseat base in dh's car.
We have a bouncy seat upstairs and downstairs (both hand-me-downs) and we use them all the time.
Our baby hates the swing, so I suggest you try one out with baby before buying one.
We do use the infant tub with a hammock all the time, our sinks aren't big enough, and the hammock makes it easier.
We wanted a convertible crib, have one, but I have to admit, she's still in our room, at 4 1/2 months, so we haven't used it yet, but I'm still glad we got it, because I'd be too busy now.
Our changing table is great, and she loves being eye to eye, instead of on the floor.
Yes, onsies, diapers (we use 7th generation, they are fine), wipes, pacifiers if you're going to use them, our daughter won't take them, spit up clothes, washclothes (the delicate soft kind), towels, a couple of blankets.
I use the bjorn all the time. I have a sling too, she falls asleep in it, but I find it very awkward - it's a maya wrap.
Bottle stuff (we like Dr. Browns) if you're bottle feeding - I had intended to breastfeed, she wouldn't take it, so now she's on exclusively pumped breastmilk - you never know. I have a medela pump in style, it's been invaluable.
Probably our biggest asset is our ambybaby, a sort of hammock you can find online - our daughter had reflux, and it was a 3 am online desperate purchase to get her to sleep - now, at 4 1/2 months, she sleeps well in it every night.
Good luck! Don't worry about having it all at first - you just need a few basics - diapers, clothes, clothes, feeding stuff - the rest you'll find as you go along, and it would be very helpful for you if you put giftcards on your registry.