It really is different for everyone so you may find you need to trade an "essential" for something else but unfortunately you can't know until your baby is here which is the stinger.
DC1:
Moses basket - he liked his bed and the continuity of being able to move it up and downstairs. He was 54cm at birth but lasted until 4 months.
Fisher price baby - toddler rocker - He would spend ages sitting around just watching everyone in there and happily used it as a reading chair until 3 years old.
Lie flat pram/pushchair - I could walk for hours and he would nap or lie around being nosey with the hood pushed back. Never been keen on the bucket style seats where legs are always raised.
DC2:
V cushion - used for feeding, learning to sit and as a sleep prop because she didn't like being flat on her back.
Sling - meant I could get on with life without the constant screaming, also handy for feeding on the move.
Baby swing - literally the only place she would be put down for the first 6 months of her life!
The Mamas and Papas Ergonomic bath was a godsend for both as it meant I could bath them hands free.