You'll probably quickly learn that there are many differing opinions out there! Alot of it varies based on the parents preferences and then also the individual baby.
I'll share some of the life savers for us: A low reclining bouncy chair that vibrated for when our son was a newborn, and then a little more upright one with more bells and whistles as he got older, a swing (I would encourage one that is almost like a bed when a newborn but can be more upright as he/she gets older), Tiny Love Black/Red/White gym, a sound machine, a simple exersaucer, some type of baby carrier (which one really depends on you and then what your baby will tolerate), a stroller frame that the infant car seat just snapped into, and then a really nice stroller the baby could grow up in (I personally was not a fan of the combo sets, but that was just us), a kick toy (but the best one out there is not made anymore...I found it at Once Upon a Child), a dresser/changing table combo, a fast read thermometer (not the ones that come in a kit or the ones for ears), infant seat cover to keep baby warm until summer, an extra head support, next step in car seat, high chair, booster seat, deluxe diaper bag, Medela Pump In Stlye Advance Breast Pump, GOOD stain remover such as OxyClean and Zout (test first to make sure baby is not sensitive to), Aquaphor, lots of baby wipes.
Things that were nice: several brands of pacifiers, several brands of bottles, a diaper pail (we've tried several, but I think I like the Diaper Champ the best), a changing pad with at least 2 covers, newborn and size 1 diapers, burp clothes or cloth diapers for this purpose, crib sheets and waterproof pads, extra small waterproof pads to use in varies places in case of leaks or spitups, simple onsies in several sizes, a pack of bibs (velcro), eating set, small wash clothes, a couple baby towels with hoods, a sleep sack, swaddler, baby book, Desitin Orignial, Aveeno or other more natural baby wash and lotion, baby clothes in bigger sizes, pack n play (but we did not need the ultra deluxe one we got!), baby gates, a few basic baby proof items, baby monitor (we did not have video but that would be a nice extra), vaporizer, books for baby, books for parents, teethers, rattles, toys up to 9 months (then you can get more at Christmas), Robeez, a mirror for baby in car, a mirror so parents can see baby in car, simple infant seat toys, car seat protector, car shades unless you have tinted windows, infant toothbrush and toothpaste, pacifier clip, nursing pillows if nursing (I liked My Brest Friend when first learning and then Bobby pillows as I got the hang of it!), hooter hider for nursing, cart cover for germs and comfort,something you are OK with as a lovey when child gets older, bottle drier, microwave sterilizer (for pacifiers and/or bottles), substantial bibs for when baby starts food, back carrier if you lead an active lifestyle, front carrier for when baby is able to hold head up, high chair toys, 1 or 2 nice lullaby CD's,
What we were given that was not necesaary: Wipe warmer, bottle warmer, grooming kit, medical kit, baby product kit, baby oil, baby powder, Vaseline, baby medicine, way too many blankets, way too many bibs, way too many stuffed animals, odds and ends of momentos, Baby Einstein DVD's (our son did not get into them...try from library first!), Dreft (use something like 7th Generation instead...Dreft has perfumes and such that can be irritating.)
I used the baby comb, snot clearer, vaseline, tub and such from the hospital. I also just used Olive Oil for Cradle Cap instead of Baby Oil. I tend to like to go natural for the most part, but I was not able to find a natural solution for stains.
I'm sure I've missed things, but I hope this helps. I wish I had gotten help with my registry. Oh...register at a couple places. Target and BabiesRUs, or something like that.
Have fun and best wishes.