Unless you've been away on holiday today, you'll have noticed that Apple's announced Bootcamp, which provides the necessary drivers (and simplifed Apple setup) to allow a Windows CD to install onto an intel-compatible Mac. There's been a flurry of firmware updates for intel mac platforms, almost certainly to enable the new boot firmware to allow the Bootcamp to work.
The Register even plays into the action, simulating a timeline which predicts the demise of Mac OS X as cross-platform producers such as Microsoft and Adobe give up and move their applications only to supporting Windows systems. Either way around, the chances are it's going to be good for Apple's share price in the short term.
However, unlike the demise of Mac OS X, it's going to open up Mac Book Pros for a wealth of corporate customers who wouldn't dream of obtaining a PowerBook before. Even if they only run Windows on it, it's still a good piece of kit for the money; and Apple makes money from hardware, not software. Having said that, it's far more likely that a PowerBook will have both Mac OS X and Windows on the same hard drive, rather than exclusively one or the other. And that means that more people who may not have considered using Mac OS X will at least see what it looks like.
Of course, dual-boot isn't great. You have to shut one machine down to start the other one up; and even if there's some nice hibernation features, it still takes time to context switch between the two. What's really likely to start selling the package is when the hardware supports virtualisation; which is the abillity to run two operating systems concurrently. When that happens, expect to see people running both at the same time; maybe Mac OS X for the creative tasks (iPhoto) and Windows for business tasks (Excel). Make the computers able to share the same network, and you've got a way of moving data backwards and forwards between the two. Show them that it's possible to run Office under Mac OS X, and they may wonder what they needed to run Windows for in the first place.
It's a smart strategy for Apple because it will help shift hardware, and that's where the money is. There may be some people who run with just Windows, but they'll be in the minority. Maybe students will shell out for more powerful dual-core processors so that they can run games in Windows and do their work in Mac OS X. And all the money for hardware will go to help create better software (as well as better hardware) for the future.
Expect the Mac Book Pros to have long wait lists on the Apple Store for a while.