This post may actually relieve some people -- I strongly recommend not trying too hard to finish decorating the entire nursery before the baby arrives. Even though you have way more time and ability to focus before baby arrives, once they get to be 6 months, 9 months, 1 year old, they start having much more appreciation for decorations and things on the wall, and they get really excited to see something new go up.
Not to mention, adding decorations as you go keeps the room fresh and interesting, and allows you to put stuff up as you get to know your baby.
The other advantage to waiting, even on some of the baby products and furniture decisions, is that nothing compares to the perspective you get after baby arrives -- you learn a lot when you actually have to take care of a baby.