Okay, while I'm waiting for my new fluffy prefolds to get here, I thought I'd post about nursing bras and tanks. There are a lot of them, and it takes time to weed through and find the ones that will work for you.
First, let's talk about bras. First rule of nursing bras is no more underwires. Not allowed. They can cause plugged ducts, and you really don't want that. You need to find a bra that fits well and is not too tight. Tight bras can also cause plugged ducts. You will probably not be able to wear anything you wore pre-pregnancy. You can find nursing bras and tanks at Target that will work pretty well if you're not particularly large-busted. But I am, ahem, well endowed on top. So, I need support. I ended up at a locally-owned maternity store and tried on a ton. I finally ended up buying a Bravado bra. It was not cheap, but I figured I'll be wearing it for the next couple of years, so it's worth the investment. No, it doesn't fit as well as my beautiful Victoria's Secret bras used to, but hey, what are you going to do?
Next, nursing tanks. I love nursing tanks, but it is really really hard to find one that will support me well enough to get away with not wearing a bra under it. And if you have to wear a bra under it, it defeats the purpose. The one I finally found that I loved is made by Glamour Mom. It comes with a built-in nursing bra and is really well made. Again, it's an investment. But I would suggest getting one or two of these while you are still pregnant. They are designed to fit during pregnancy and to hide extra "flab" post-partum. It takes a while for your belly to look "normal" again after it's been carrying an 8 pound baby for a few months.
Also, during those last couple of month of pregnancy, I found that I couldn't wear underwires anymore because they dug into the top of my belly and were super uncomfortable. Nursing bras and tanks are a great option. However, don't go out and buy an entire stash of really expensive bras until after your milk has come in. Your breasts are going to get bigger, I promise, and you will be sorry. The tanks are okay since they're more for a "range" of sizes, but err on the side of big.
Once your baby is born, give yourself a couple of weeks to get accustomed to your new body, then see if you can find a local store where you can try things on. Ask a sales lady to help you and measure you. And it's better to go when you're kind of "full", not right after you've fed the baby or pumped.
A sleep bra is also a really nice thing to have. I just have a couple of organic cotton sleep bras. They're very loose and you just pull them down when you need to nurse. Makes life a bit easier.
The first couple of months, while your body is trying to figure out just how much milk to make for your little one, you are going to leak like crazy. You'll need nursing pads. I bought some washable organic cotton ones, but found that they left me looking like I had headlights on my chest. I ended up getting disposable ones because they are much thinner and more subtle. Get some with adhesive if you can so they'll stick to your bra and stay in place. After the first few months, your body settles in, and you'll stop leaking, so you won't need these for too long.
Hope this helps some mamas out there and maybe even saves you some time and money!