The girls wear a onesie and pants most of the time. Occasionally a sleep and play. They wore sleep and plays exclusively the first two months or so then around 2/2.5 months I switched them to a onesie and pants.
I want to send her in Sleep and Plays because that's what I have the most of and they make diaper changes easy. We only have a few romper/creeper type outfits and she tends to be colder in those if the AC is on. I hate putting on/taking off pants - sleep and plays are so much easier.
We don't start daycare for another few months, but C usually wears a onesie and pants or shorts, or sometimes a romper. Sometimes he'll wear a t-shirt instead of a onesie. In the summer he doesn't usually wear socks, but I'll keep some in the diaper bag in case he needs them.