Jammies- these are the best! You want to make sure they are one-piece and footed, so that middle of the night diaper changes are as easy as possible (nothing to pull over the head/ figure out legs in right places when it's dark) and baby stays nice and warm, 7 per size.
Onesies (bodysuits)- so this is what the whole baby wardrobe is based on. You will change multiple outfits a day because of bodily fluids. I would say about half long sleeve and half short sleeve because even in the summer small babies need to be kept warm (especially if you have AC), 14 per size.
Pants- they keep baby warm, but you won't always use them. The footed cotton ones make your life so easy because don't have to mess with socks, 5 per size.
Nice outfits- these include nice little button down shirts, or jeans, or some other impractical outfit. They are a pain to put on, so not very practical, but still nice to have around, 2 outfits per size. (Most likely you will be gifted these, so don't worry about buying them yourself).
Socks- several, especially if you get lots of pants that aren't footed. They are a pain, but at least they look cute and keep baby toes warm.
Hats- several, brimmed for the sun, caps for the cold.
Bibs- your call. I find them useless because the kid will inevitably spit up on his outfit anyway, but maybe for later on.
Other- sweaters and jackets for cold weather, bathing suit (swim diaper) for the summer, rompers (they look cute).