need to create 2nd iTunes library from the 1st

My wife and I each have iPhones and we're using 1 Mac. We backed up our 1 collective iTunes library from our PC, and now it's on the Mac, under my user acct.

I debated for a while using 2 diff user accts on the Mac vs. using 1 user acct & 2 iTunes libraries (hitting Option key when opening iTunes). I decided we didn't mind the logging in and out once a week or so for syncing, and it would provide the cleanest solution (folder architecture esp.) for our music/vid/pic/contact/app syncing on the iPhones....so I think we're rolling with the 2 diff user accts method.

With that said, what is the easiest way for us to each get our own library whittled down (getting rid of the stuff from other person we don't like)? My user acct has the entire library, all of our apps (i just uncheck hers/ones i don't want, for now), etc.. Should I log-in as my wife, hook up the external HD (our iTunes backup), load her the entire library as well, and then she can delete stuff she doesn't want?

I have researched this on Google for the better part of one night, and am turning to the forums now.

Just have your wife create a playlist of what she wants on her iPhone and have her sync (Auto or manually) that playlist to her phone. If she chooses manual she sync multiple play lists to her phone or she can just drag and drop music from the library onto the iPhone as she desires. In fact, I'd recommend you both do this using manual sync vice auto sync. That way you each have access to the whole library but only load what you want instead of everything.