Another thing I've noticed is that some people are planners, and particular about the kinds of things they want. I can't imagine my friend Amy sending her DH Adam off to the shop by himself to get something for the baby, for example. She would never have said, "Just go get a pacifier," because she'd have quite exact specifications in mind and might have to see the selection for herself. And, even if for some reason she didn't much care, Adam would never have felt comfortable going off to choose by himself. He'd be more likely to come home with six different things, then run the ones she didn't want back to the store. To him they would all look alike.
On the other hand, I have heard about over-planning--the newborn-size clothes, for example, which the baby might grow out of quickly (or never really fit). And apparently different brands of diapers fit different body types, and you don't know what you're going to get until the baby's born, so if you've stocked up on Huggies, you may find that they don't actually work for your child. I've heard that a good baby shower gift is a "sampler pack" of diapers from different brands--like the smallest package of each brand you can find, so the parents can try them out once they have the baby.