It was a really satisfying exercise. I don't know why it took me so long to work up the energy to tackle it (it was on my list of things I wanted to do before the baby was born).
I ended up leaving one shelf half-empty (amazing!) and Zuzu actually commented on it: "Oh, Mama! It's all gone!"
Don't worry, Zu. I'm sure it won't take anytime at all to fill it up again.
Of course, I "put away" a lot of stuff into the closet in the guest room, which is kind of a disaster... But you know. Another project for another day. In the meantime, I'm keeping the door open to Zuzu's closet and feeling ridiculously proud of myself everytime I catch a glimpse of its nicely organized contents.