I just want to point you to a great article over at Creative COW that addresses a timely topic.
"Forget all the rumors and speculation about Final Cut Pro X, Creative Cow Contributing Editor David Roth Weiss delivers nothing but facts as he guides you through the steps necessary to partition your Mac system drive with a cool multi-boot setup that will allow you to easily and efficiently switch back and forth between different versions of Final Cut Pro, between different operating systems, or all of the above."
Be sure to head over for the whole article. A must read.