-Safe place for baby to sleep if you don't plan on bedsharing (crib, bassinet, pnp)
-Breast pump, bottles, binkies
-Baby's clothes, towels, washcloths, blankets, baby sling, etc.
-Any toiletries for baby (rash creams, baby wash, etc.)
-Maybe a bouncer/rocker chair, a stroller if you plan to use it.
-Diapers and wipes
Those are really the only "essential" items I can think of. Everything else you can pretty much live without.