Mac does Windows?!?
UPDATE: Having now thought about this for at least some portion of the last 10 hours, here's where I think Apple is headed with this. Given that Leopard will not arrive until mid-year (and likely in developer preview mode at that), I am imagining that the end game for this technology is to allow Windows to be operating within an OS X "window", ala Virtual PC. This would yield all the performance benefits for both environments and make it far more useful than simply dual-booting. Until start up and shutdown time become instantaneous, having to reboot to switch environments is a non-starter for wide-spread use in my opinion. And even with instantaneous startup/shutdown, it's far less useful. However, operating simultaneously and sharing file spaces would be the ultimate in usability and with OS X as the "host" and Windows as the "slave", you can see where the perceived upper hand would be. I'd also expect that the reaction from the larger developer community would be to move more Win-only apps into the OS X environment.
UPDATE 2: This is what I'm talking about. If you don't want to click, it's a beta claiming to be the "First Vitualization Solution for Intel-powered Macs" that claims concurrent use of OS X, Windows as well as Linux. While this is a geek-step, it won't get broad use (in my opinion) until Apple includes similar capabilities as standard fare with OS X.