when to start baby registry

Katie
I really screwed up when I built my wedding registry I.e. We didn't get many useful things. So I really wanna take my time to do the baby registry. So a couple questions:
1) when is it too early to start building it?
     (When did you start)
2) What things did you register for that were lifesavers? Bummers?
3) What didn't you register for that you wish you had?