Some things I've found useful that I've also given as gifts:
The Ultimate Crib Sheet by Basic Comfort - snaps on top of regular fitted crib sheet and has waterproof liner - you still see the pattern of the fitted sheet on the side of the crib, and it's SO much easier to change than a fitted crib sheet
Halo Sleep Sacks - get the larger sizes so she'll have them ready when winter weather hits
The "Emergency Diaper Bag" - a portable changer kit (I used one by the First Years - foldable changing pad with a wipes case and pockets to hold supplies - about $10 at Target), a couple onesies, diapers and wipes, hand sanitizer, burp rags, plastic bags (like newspaper bags, folded up and tucked into one of the pockets), receiving blanket, maybe a couple granola bars or other type of shelf-stable snack (nursing moms can get REALLY hungry) and a grown-up size t-shirt (because when "spit happens" sometimes the adult gets it too!). Put it in a simple bag - could be something like a reusable grocery bag or a hospital freebie diaper bag - and write a little card saying that this kit goes in the trunk of the car *now* because sometime in the course of new parent sleeplessness they'll go out with the babies and either forget the diaper bag or forget something important in the diaper bag.