This thread might get some more action in the "Windows on the Mac" forum.
Anyway, here's my 2 cents. YMMV.
I think you should have 2 partition, one for Tiger and one for Leopard. I'm not a fan of bootcamp at all. Of course, I don't play games so I don't need all the extra horsepower that comes from running Windows natively. I use VMware. There is a big debate on whether VMware or Parallels is better. I started on Parallels, but it gave me too many kernel panics for me to tolerate it. I tried the demo of VMware and used their converter to make my Parallels virtual machine into a VMware machine. That worked flawlessly and I've not had a kernel panic since. The reason I don't like bootcamp is because I can't contain and "protect" Windows, per se. I like to have Windows contained within a virtual system. I make backup copies of this system on my external drive. That way, once Windows gets junked up over time, I can delete the virtual machine and then quickly copy the backed up fresh one and then I have a nice, fast, and non-junked Windows. It makes it much easier to deal with all the malware out there.
YMMV.
EDIT: I are dumb. I just realized you were asking about Linux. That's a lot different than Windows. I'm not sure if you can have a Linux partition on a Mac. This is outside my expertise. I have experimented with Linux within Parallels (not VMware), and I wasn't all that overly impressed. I do know that you can download pre-made Linux systems (called "appliances") for free from VMware and you'll be up and running Linux in no time.
