Partioning and booting muiltiple OSes off of a Portable Drive

First off sorry for the long title, second sorry if this just doesn't seem to fit. My goal is to create 4 partitions on my portable Hard Drive, 1 for a boot manager that can let me choose which OS to load (and choose between my external and the local drive) 2 a Windows XP Partition, 3 a Knoppix Partition, 4 just a regular data partition for Portable FireFox and such. I plan on using Qemu to emulate the partitions when I'm on library systems and the built in boot manager for when I'm on my home computer (Which is actually my moms computer). I need to know how safe this would be (for all systems involved), what boot manager to use, and what kind of partitions to use for these. That should do it, and I do have XP Pro installer, I'm going to download Knoppix-Unfortunately I'm about to be kicked off though and won't be able to finish downloading (stupid library limits, I JUST got on.)