Yes, that's basically what I do, SideshowBob. I have a 486 with DOS and Windows 3.1, a Pentium with Windows 95, a Pentium II with Windows 98, and a Pentium IV with Windows XP.
I sorely need to upgrade my 5-year-old Pentium IV, but I'm waiting for Windows Vista to launch so I can have a different operating system on each computer.