Pretty extensive list, trotw00d. However, there are a few additions I'd like to make.
Crib - I know, this is on the list above. But, it's listed as necessary. It's not. Seriously, my little one didn't get a crib until he was six months old, and he has slept in it maybe 4 times since then (to date, he is 15 1/2 months old). Baby can sleep in mommy's bed. It's called co sleep. Co sleeping really helps breastfeeding mommies get more sleep. But do research first. Not everyone should co sleep, such as those on medications which make one drowsy, or the obese.
Sling/wrap - This is like a pouch in which a baby is stored, worn over the parent's chest. It allows a parent to cuddle with baby while getting things done, like house cleaning and such. If you use a sling, you may not need a stroller.
Onesies and sleepers - You can never have enough onesies or undershirts. You'd think that, with a diaper strapped to his ass, he could avoid wetting the bed. No matter how many times you change baby's diaper or what brand of diaper baby wears, he will wet the bed, soaking all of his clothing. Try to get most of baby's clothing as hand-me-downs, as baby will grow out of them in the blink of an eye. Sleepers aren't as important unless baby lives in a cold house.
Stuff for breastfeeding mommies "What's good for mommy is good for baby!"
Nipple cream, generally Lanolin-based, soothes chapped nipples. Sometimes, mommy's nipples get cracked or blistered while baby and mommy are learning how to feed. Nipple cream is like chapstick for nipples. Remember, a little goes a long way!
Nursing bras - The difference between regular bras and nursing bras is that nursing bras have a flap which comes down to expose part of the breast. Very handy for discreet breastfeeding in public. Most breasts grow quite a bit during the first week postpartum, so don't buy too many until mommy's milk comes in, but buy a few as they are very handy for feeding.
Nursing pads - These are like maxis for your breasts! There's nothing quite like hearing your baby cry and then soaking the front of your shirt with breast milk. Very annoying! Nursing pads are a must for nursing mommies and non-nursing mommies alike. Even if mommy isn't breastfeeding, she may still leak until her body figures out that she doesn't need the milk. Unfortunately, if you get the wrong brand, it looks like you've stuffed your bra with wadded toilet paper. Look for ones labeled "contoured." (You'd think they would all be contoured, as they are worn over breasts!) Gerber disposable medium flow nursing pads are rather discreet in my experience. And they serve the purpose. You could also purchase reusable pads for rather cheap. Or you could also make your own by cutting circles out of cloth diapers.
Breast pumps - If mommy plans to return to work, a large high grade pump is necessary. Something like Medela Pump-in-Style ($280). This sounds expensive, but consider the cost if you plan to feed baby formula (cost of formula, more bottles, missed work to take care of a sick baby, doctor's bills, etc). If mommy plans to stay home with baby, a smaller, cheaper pump would do. My lactation consultant suggested Avent's manual pump (around $20) or Medela Mini Electric ($70 online), which converts to a manual pump in case you run out of batteries and don't have access to an electric outlet.
Oh yes, and babies need oxygen...lots of it. Thank you Master Villain.