Win7 network settings: Home vs. work/public

Amazed recently at how easy it is to set up a home wireless network with Win7, with computers seeing each other with minimal fuss. Of course slightly disturbing (but very helpful at the time because wanting to transfer a lot of files) was how much access I had to my other Win7 Pro computer on the home network without any request for authorisation.

My concern is of course that anyone who can get into the network (i.e. get pass the wireless router's WPA-Personal/TKIP) has relatively unfettered access to my systems.

Am I being paranoid? Should I put the Windows network setting as public instead?

On a slightly non-windows hardening note, is it worth hiding the wireless network in the router settings?