First of all, refrain from buying outfits that don't have snaps in the crotch or are hard to get on and off. They may be cute but just aren't practical. Nice soft sleepers (Carters are great) are best for a newborn. It is also nice to get clothes in bigger sizes like 6-9 months because most people tend to buy smaller sizes for gifts. Gift cards may seem impersonal to some but are really great because then she can pick out some stuff she likes without the expense. You could always buy a small gift and give a gift card with it.
Books are wonderful. Diapers and wipes are great too! You can never have enough of those... Oh, and if she scrapbooks a gift card to a scrap store or some baby boy scrap accessories is an awesome gift! And for her... depending what you want to spend a gift certificate for a massage or pedicure and volunteer to babysit when she goes!
It's often a good idea to buy older clothes and toys for the baby - everyone seems to buy newborn items which the child soon grows out of but I've found it useful to buy items for when they are a little older. Failing that, nappies are always a great idea - a baby gets through so many it's unreal and some 'soon to be mums' just ask that everyone buys a box or two of nappies in different ages/sizes.
Some nice things you can get are bibs, socks, onesies (you can never have to many). For the mom you should get things that are relaxing. Anything with Lavender is said to be relaxing. Bath and Body Works sells this Lavender pillow spray. I recieved this as a gift when I had my baby and it was really nice. It smells very nice and is soothing. Maybe you could give some restaurant gift cards and offering free babysitting. New mothers can definetly use some time to themselves.
Here is a great useful idea! You should offer to watch the baby why she sleeps that was the best for me I needed some sleep and the help was wonderful. You don't even have to leave the house just hold him while she sleeps or help her do house work.
Finally, I would get a nice sized basket, and fill it with small items you think the baby could use, and also add some nice things for the mother, like bubble bath, scented candles, a book about babies first years. Then wrap it up in a receiving blanket.
About the Author
Frederic Lampard is the owner of http://www.personalizedbabygift1.info - a website dedicated to baby gifts.