Configuring macbook pro

Hi Guys,
I have the following requirements to implement in my macbook pro( which i am about to buy)

I have to run follwing 3 in it...
1. Home XP for personal use (i will start migrating to Mac as fast as i can, but for now I have to live with it)
2. Office work, XP (always going to be XP , no choice there)
3. Kubuntu (occasional office and personal study related)

I am buying a refurbished MBP which unfortunately comes with only 320GB. So I have the following options...

1. Upgrade it to 500GB. And allocate 250GB for office and run using bootcamp. And in the Mac partition, i will create a VM and run personal XP and kubuntu from there.

2. Use the 320GB as Mac partition. And use an external hard drive with firewire 800 (oxford 1.5TB 1500GB eSATA~FireWire 800~USB External Hard Drive, available in ebay for $240) and load office XP image and boot from it.

Can you please suggest which one would be better option? (I understand the performance problem running from a external hard drive, but firewire 800 makes it better?) And if you have any alternative suggestions.

Thanks a lot for the help. Appreciate it

 

Actually office management has prohibited using office domain from VM. (they say they can't trace the account from insdie of the VM)