What is the best way for two people to keep their music separate on one shared PC? My SWMBO (wife) and I share a PC. She has an iPod and has all of her music on iTunes on the shared PC.

I envision 3 types of music:

1. Songs that both of us like and both want on our own iPod.
2. Songs that she likes and wants on her iPod, but I don't want
3. Songs that I like and want on my iPod, but she doesn't want

Should we just set up two separate playlists -- one for her, and one for me. Or should we install two completely separate copies of iTunes? What's the best solution.

We have a Windows XP system, but I've got a new PC on order with Windows Medial Center that will replace the current PC.