I've been using dedicated (physically separate) disks for my OSes (I run Windows and some flavor of Unix or Linux at any given time) and find it is far easier and less time consuming to maintain physical separation. I get this is easier said than done on a Desktop class PC/workstation as opposed to, say, laptops, but then again there's no reason you couldn't hook up a relatively inexpensive external hard drive to run one of your *nix-y OSes. A quick 'F8' or 'F2' or whatever your variant of BIOS hotkey, will present a HDD selection menu to boot up the appropriate OS. Really makes me curious why folks still dual boot.