OSNews points out that “Ars reviews Parallels Desktop for MacOS X, and concludes: “People pondering the switch to a MacBook can rest assured that with the exception of USB device support and hardware accelerated 3-D applications, their needs will be well met by this little workhorse of a program. Between the networking that just works, the impressive speed and the inability of the client operating systems to know they are running within a 'virtual machine', I think you'll be hard-pressed to find software for any x86 OS that doesn't work within a Parallels VM.”
It's hard to imagine a more desirable machine than a laptop or desktop with dual-core processors and the ability to run Windows, OS X and Linux in separate virtual machines.