It's really personal on most things.
Like some pp said baby bath, but I have only showers in my house so a baby bath is necessary ( although bought the one from Asda as it was cheap).
Some said baby monitor, but baby sleeps on second floor and I have my living area ground floor. Baby monitor was essential as I can't hear a thing from downstairs. I'll actually sell my normal one and buy one with a video.
My daughter loved baby bouncer( I bought it for £5 on market) and bumbo Seat was useful for when we were at others. Also used bumbo for shower once she was able to sit. Bought for £5 on market. I sold both afterward and got my money back.
As my last baby was my third I had a rough idea of what I needed, but still I waited for baby to be born and then I bought stuff I taught we needed.
Even nappies, didn't buy tones before as with DS1 had problems with all nappies apart from Pampers. In fact DD was the same, but couldn't know until I tried some.
I didn't buy a special nappy bin, a small one did the thing for me, and I changed it daily as baby's poop every nappy and smelled. Much cheaper for me this way.
Some clothes I received were nice and lovely but a bit pointless as difficult to change a nappy with so many layers and also didn't look comfortable for baby. Ended up using some only once for church. I wouldn't have bought them myself.
Loved my sling and baby carrier, so pram for newborn was a bit of a waste( anyways bought it second hand). I found a lighter on that recliner completely and it's also parent faced is more useful( at least for me).
Agree with diaper bags. A normal backpack does the job and doesn't kill your arm because of the weight.