While I was pregnant, I lived by newborn essential lists and product reviews. There is SO much out there, I didn't want to waste money and I didn't want a bunch of stuff that went unused. Between baby showers gifts and online shopping, I aquired a good amount of baby items and there have definitely been a few essentials that have become my favorites..

Fisher-Price Newborn Rock 'n Play Sleeper - Love this thing...we scoot it all around the house and take it on overnight trips. It's portable and baby sure does find it to be super cozy.
Sckoon Booties - The ONLY thing that will stay on my babe's feet and they're also pretty cute.
Avent Soothie Pacifiers - It's a good pacifier, what else can I say.
Boppy - Comfy for breastfeeding, perfect for propping up the baby, and makes a good travel pillow for me :)
Boba Wrap - Baby wearing is one of my favorite things and once you can figure out how this enormous piece of fabric works..then you're in for a sweet experience.
Evenflo Glass Bottles - I picked up a few of these as back-up because they were small and super cheap -- they turned out to be awesome because they are simple with few parts to clean!
Aden + Anais Swaddle Blankets - We use these to swaddle, as a nursing cover, as a blanket, etc... Super soft and a great size.
Motorola Video Monitor - An expensive item but so awesome. I love watching her wiggle around in her sleep.