I would say:

1/ Baby bath as Kaitlyn was using our bath by 4 weeks
2/ Baby monitor ....unless you have a big house and you plan on spending lots of time at the end of your yard away from the house you will hear you little one crying out for you.
3/...thats it actually

One thing that I REALLY used and only got when Kaitlyn was two months and could have had from earlier on was a bouncer for her to lay in ..really helped if I needed to do something and she was up. She still sits in it if I am DESPERATE and need to have a shower...she is getting WAY to big for it but if I need to keep her in one place it works hehe. I also got a change table with the compartments below and that was good as I keep all her "spew rags" , nappies and other bits and pieces under there for easy access!.

CAss