Yet Another iTunes Question

Okay, so here's the deal: my girlfriend and I share one computer.  We also shared one iPod up until now but are getting a 2nd one today.  Being a fucking anal-retentive organizational kind of guy, I HATE it when the iTunes Library gets all bloated.  Meaning I would prefer not to mix our sizable music collections into the same library.  I'm pretty sure there isn't, but I have to ask--is there some way to create profiles, or ANY method actually that will allow us to keep our music libraries seperate?

Yes, I know about ml_ipod, yes, I know iTunes is retarded, yes, I know iPods are faggotry, please just answer with the facts I've given :( If it is indeed impossible, please suggest alternatives.

Well, I'd suggest winamp. It now has defualt Ipod support, and can have it so that each user have thier own library.

But thats on windows XP, so if you don't have that, then I don't know.