after having five, I would recommend the following......
muslins.....very practical with sicky babies, and now for everything else.
a cradle....I got a large crib/cradle on a stand and was big enough for mine until at least 5mths...2 were 7mths and pulled themselves up to standing before I realised they needed a cot. (mind, both were still under 16lb on their first B/days!)
A travel system with an in-car base.....sooooo wish they had these 12yrs ago.
high chair
swing....made its money's worth the first day. DS1 slept for 3hrs for the first time since birth the day we got ours....he was 5wks old by then!!!!
OOOh...and also pay for cranial osteopathy....well worth it!!!(i know that is six, but all were what I couldn't live without. could go on too....Kamillisan was another, and sudocreme. and a sling)
PLUS...a changing unit in the lounge.....invaluable!(sorry, will try to stop now with the pluses
and what you can go without...
a baby bath.....a sink works perfectly, and is the right height to help relieve your back.
baby toiletries.....top to toe wash is the only thing I have used with regularity.
bibs....with mine and their projectile vomiting, they went over the bibs, and got everything else!!
matching bedding.....looks nice, but so expensive and they grow out of the need so quickly. Grobags much more practical .
snowsuits. If in a decent pushchair with a cosy toes, they will bake if also in a snowsuit. Blankets work well, and you can layer.
But the very best thing a new mum needs is a great friend who is already a mum, a dose of common sense, and MUMSNET