Virtual Machines or Multi-Booting?

In the next few days, I plan on wiping my laptop to clear out the clutter and regain a little performance. I'm just debating between splitting the drive up and multibooting with XP, Vista, and CentOS 5 or just installing Vista and running XP and CentOS in VMWare. I did look into Xen, but it sometimes has an issue with wireless cards, which tosses that idea out as far as my laptop goes.

Also, any performance differences between Vista Home Premium w/SP1 and Vista Business w/SP1? The laptop came with Home Premium, but I have a legit license for Business and was planning on going with Business.