I got way too much stuff when I had my first. I realized by #3 that I needed much less. If I was doing it over again with 20/20 hindsight, my lists would be much shorter.
Needs:
Car seat - I got a Britax for DD, she used it from her first car ride until a few weeks ago (she's almost 6).
Diapers - If you use cloth, then between 12 and 20 diapers (I preferred FuzziBunz), cloth washrags as wipes, waterproof pail liner, and a diaper pail or trash can with lid.
Breast pump and bottles - If you are going to be working.
Clothes - I liked sleep sacks for night time - made diaper changes easier. You likely won't need to buy infant clothes though; people seem to love to give clothes as gifts.
Receiving blankets and instructions on how to turn your baby into a burrito (aka swaddling)
Good for Mom's sanity:
Vibrating bouncy seat
Baby carrier - I had several and liked my Hotslings best until about 6 months and then loved my Ergo carrier
Stroller
Thermometer and emergency supply of Baby Tylenol, Mylicon drops, & diaper cream
Name and contact information for your local mom's club
Will likely want later:
Crib - I started using for naps around four months, didn't use before then.
Booster seat with tray - I prefer to a high chair - smaller, can wash whole thing, easy to take to other places - won't need until 6 months or later
Some babies love 'em, some babies hate 'em - might want to borrow one until you figure out which kind you have:
Swing
Exersaucers
Baby bath tub
Pacifiers fall into this category too, but you'd probably want to just buy one.
I liked having a changing table (I like any sort of organization product though), but you could also just get a changing pad and skip the table.
Best wishes!