Ok, I want to make a partition on one of my hard drives available to the Wench over the network so she can keep a backup of things on her laptop.

Ideally I'd like it to be that when one tries to access the drive over the network that it just requires a password; is this possible or do I have to go down the whole user account route?

I'm running Windows 7 Enterprise so have most tools available.

You need user accounts on the host, to make it easy, you should have the same account name and password on the other machine, but that is optional, but you need to enter them when you attach to the drive (mapping the drive and storing the password means it is a one-time affair, but less secure, if you don't have to log onto the laptop).

I have always used user accounts on my computers, I've never had a Windows, Mac or Linux machine I didn't have to log into, even when I lived alone. Maybe it was my mainframe background, which made me paranoid about security.

Yeah, after a spot of googling that did seem to be the case. Set it up last night and it's all working fine.