With my first, there were so many things that never got used, and a few things I headed out to get when he was 2 days old.
Clothes - really, don't bother. Between hand-me-downs and gifts, you're not going to need to buy clothes for a while. The one exception to this (for me) was baby legs. My guy wore the same 3 or 4 tee shirts, maybe 1 or 2 sleepers and that was it for the NB size (we used wool most of the time). But I only needed maybe 2 pairs of BL - I had about a dozen and most of them went unused.
Breastfeeding pillow - I went out to buy this when he was less than 2 days old. I really needed it, the couch pillows just weren't enough support. And he used it until he was almost 2, it was his favorite pillow to lay on the floor with, snuggle on the couch, etc. Now it's sitting and waiting for #2 to arrive. I did get one that is slip-covered, and I'm going to buy a spare slip-cover this time. Spit up, blow outs, and even just dripping milk can make it nasty quick.
Bulb syringe... heck, the whole first aid kit - never used. I don't like bulb syringes, I prefer the nose frida, which is much more gentle and less invasive. And the nail clippers in there are super dull, I'd rather be careful with sharp ones (on the premise that in the kitchen you're more likely to get cut with a dull knife than a sharp one). The medication measuring spoon just isn't necessary, since most medications come with their own measurement device.
Baby shampoo, conditioner, soaps, lotions, etc. - never used. Not true. Never used on the baby. I used the scent-free CA Baby lotion on myself. But at 2 my DS has never known shampoo or soap - there are too many nasty chemicals in most of them for me to be comfortable with. Baking soda and the occasional epsom salt bath (for rash) are far gentler and safer for baby. Even diaper rash cream, the only ones we've used are a prescription barrier cream (not zinc - for an allergic reaction), and a natural one that is olive (or is it coconut?) oil and comfrey based.
Pack and Play - We never really used it for DS, but it will most likely be used for #2, as a place that is out of DS' reach.
Convertible car seat - Honestly, this can be a big expenditure, and definitely not something to buy used. We skipped the baby bucket entirely and asked the grandparents to buy us this (and they were happy to have a big ticket item to splurge on). At up to $300, buying it later on your own can really hurt the budget. Do your research, find a store that will let you try them out in your car (for fit), make a decision and then ask someone to buy it for you.
Stroller - this is something that is very individual. Do you live in the inner city, close to everything and do a lot of walking and carrying? You'll probably want/need one. Or do you live further out and have to drive everywhere? You may not want/need one. Are you a runner? A farmer's market frequenter? These are all things to think about. Think about how you live your life, how it may change with kid(s), and go from there. Pick one that is going to suit your lifestyle, and again, ask someone else to buy it for you (grandparents can be great for this). Since you're planning on BW, you don't really need one for the early days, so one that holds a baby bucket isn't as appealing, but one that will hold a toddler might be. If you're going to be taking it grocery shopping, get one with a big basket underneath, if you're a runner or plan to use it for exercising, get a jogger, etc. This is one of those items that you can often find used, like on CL, for cheap - just check it out first and make sure it's in decent shape. Oh, and check the weight limit on these things, some of them are deceptively low. I went out when DS was 3 mos and bought a stroller because it became obvious we were going to need it. Now that he's 2, we don't use it as much, but we still use it at least weekly.
Baby bathtub - waste of money and space. I could count on one hand the number of baths DS got in his first year. If he needed washing, a water sling and a shower for mama worked well. Showers for mama can be in short supply during those early times, so a water sling can be a great investment.
White noise machine - Mama found it very calming, baby not so much.
Place to sleep - whatever this is going to mean for your family. Crib? Co-sleeper? Floor mattress? Start thinking about it and shopping around now. Things like cribs and co-sleepers can often be found cheap at consignment or CL - just check for recalls. But you pretty much always want to buy a new mattress, unless it's obviously unused. Old (used) mattresses have been linked with SIDS.
Baby monitor - again, this is a lifestyle thing. Do you live in a small space, and can hear everything from every corner of your place? Not really necessary. Are you going to have baby sleeping right nearby? Not really necessary. We live in a big old house, and can barely hear the baby from the next room without one. We didn't need one until he was about 1, since until then he was sleeping nearby, but since then we've relied upon it. IMO, video is overkill, you really just need to hear whether baby is awake or not, and any decent monitor can do that. Again, think about how you live, and do you want to be looking at a video screen every 2 minutes to check on the baby. If you're techies, I highly recommend a digital monitor, since most analog monitors get too much interference from electrical equipment. We just finally replaced our analog monitors with digital, and there's a huge difference in the (lack of) interference. Do your research, because they are not all the same. But used is just fine if you can confirm that they work - many people just outgrow the need for them.
Diapers - if you're doing sposies, obviously this is a moot topic. If you're doing cloth, do some research and make some decisions on what direction you want to go, what fits your lifestyle. These are great to get used (diaperswappers.com, the trading post here on MDC, consignment shops, and if you're near a city CL or kijiji can be great), just educate yourself before buying. Don't bother asking other (mainstream) people to buy you CDs unless you ask for a package purchase (whether this is a dozen PFs or a NB/infant package that many online stores have). Most people will look at the price of 1 CD and balk at buying multiples, and 1 CD just isn't much help. For most people, this is something they're on their own buying... people who wouldn't balk at buying 6 pkgs of sposies will often balk at buying 6 CDs. Think about all the things that go along with the dipes that you will also need - wipes, wetbags, pail liners, etc.
Humidifier - if you live in a dry climate (whether year-round or only part of the year), this is an important tool in the parent's arsenal. During those times of year when your hands feel constantly dry or the inside of your nose is cracking from the dry, the baby is in even worse shape. Having a humidifier going, especially at night, can help a lot. Research them though - many of them require disposable filters, or other parts that need constant replacing ($$). Hot steam humidifiers are not really suitable for use in a nursery because of the risk of burns, so look for a cold one.
Burp cloths, bibs, blankets, socks, slippers, washcloths, towels, these are all things that people love to give as gifts, and you're not going to die if baby arrives and you don't have any (enough). I would wait and see what you get before buying any of them.
There are many, many other things that you will see in the baby supply area of a big store like Target or even at BRU. Most of them are not necessary in the early days (or at all). Figure out what you need after baby arrives, and get it then.