This is probably one for you computer geeks

Okay so i can't log into my desktop as XP asks for passwords which I don't have. I've tried logging in as Administrator in Safe mode but that didn't work. I've resigned myself to having to re-install XP
Before I do I need to recover some files from my hard drive so to do this I've made a bootable CD of Ubuntu. Its running right now and I have access to my entire hard drive's contents but the question is what files should I definitely copy onto my external hard drive?
I'm copying across photos, music and some films i've downloaded (no, not that sort! Well, maybe one or two...). I've also copied my Favourites folder for my weblinks. Are there any other files/folders that I should copy across?