I started pretty minimal and got even more so. For the last baby I made sure I had:
breasts (or equivalent if you'll formula feed)
cloth diapers-how many depends on how often you can wash (or equivalent)
4 onsies
4 sleepers
1 nice Sunday outfit
best car seat you can afford
sling (made my own cheap one) or stroller if you like, I hated them
pack&play or some other device for keeping them safe when visiting
baby side car or bed (mine just slept with me until they slept through the night then moved to a pack and play)
I didn't use special detergent, baby wash, baby bath tub, changing table, wipe wamers, swings, toys,mobile, fancy bedding or some other things I can't think of.