Just popping in! With my first:
Secondhand (from relatives only):
Infant car seat (actually came from a close family friend, barely used)
2 playpens (they weren't really necessities but nice to have, we only needed 1 that we would have bought but had 2 in the family in great condition- one barely used)
Infant swing (only because it's expensive!)
Baby gates (not really "used".. they were already at our house, used to keep dogs out of certain rooms!)
Clothes (I accepted offers on used clothes in good condition but I haven't ended up using many as we had so many new ones.. it is nice to have for playing though or for things like dresses they'll only wear once or twice.. or just for more variety)
Diaper Genie (not really used by my good friend.. she hated it. And guess what? I do too!!
)
I bought a Bumbo off a lady on Kijiji - only because it was easy to clean and it was $25 where they sell for $65 now here and not all babies like them
Bought new:
Convertible crib (a crib we were offered was in bad condition, and we bought the convertible so we don't have to buy beds in the future)
Crib mattress (a must IMO)
Stroller (I wanted a specific stroller)
Toys, bottles, and anything that goes in their mouths really!
High chair (because I fell in love with it and didn't want a stained one)
Bouncer
Exersaucer
I plan to keep most of the stuff for baby #2, sell some things, and pass others along.
If you can afford to spend all the money on new.. go nuts.. I found taking secondhand things that were in the family freed up money to buy better quality new items and like Sarahkka said, it gave us more money to save for baby. We've started an RESP up for her which was really important to me.