I think that if you're close enough to a group of friends/family, you can register for things you need, but you will NOT need a lot of things, thus I don't see the point.
Many of your friends will be giving you gifts, more than you will need, trust me. I have 3 girls and one boy and thought maybe I'd need "new" stuff at one point since I used the same playpen, same crib, etc and things like that- people love you and your family and as a result, when this little girl is boy (yay! :)) -- they will bring baby girl outfits to the hospital, to your home, to your job, etc. You get what I mean. You will be blessed with things you did not expect, trust me when I tell you. Even for my 4th child, I didn't ask for anything - and I still get MORE than I need for my children without ever having more than 1 shower...
:)
Another thought I have that I wanted to share was this- what happens b/w my friends is when someone is pregnant, we all look and see what we can give that is LIKE NEW that we still have from our kids! I have been getting hand-me-downs that are like new for over 4 years now and do the same with all of my 4 children's clothes, shoes, etc. It saves us all money and we get to exchange great things!
If you don't already belong to one, go to www.meetup.com and join a moms group where you can meet other moms. Our moms group is having a "clothing swap" this month and even if you don't have anything to "bring" - plenty of moms are bringing things that they'd rather give to someone they KNOW than stick in a bag for a truck to come and get - KWIM?