Rounding up on 9 months of Vista being on the market, Microsoft is of course at work on Service Pack 1 which is slated for an early 2008 release. At the official Windows Vista blog, Brandon LeBlanc has offered extensive details on what the focus of Service Pack 1 is, and while much of it is targeted at businesses and independent software vendors, an interesting section outlining some of the fundamentals mentions that support for the EFI booting standard is on its way (under the Introducing Windows Vista Service Pack 1 section; there aren't any anchors I can link in this extensive post, so you'll have to search for that title or simply 'EFI').
In their hype and marketing for Boot Camp, Apple makes a pretty big deal about Intel-based Macs supporting EFI while "Windows XP, and even Vista, are stuck in the 1980s with old-fashioned BIOS" (check the sidebar of the Boot Camp page). So what could it mean if Vista catches up to the EFI bandwagon? I'm not quite sure yet. It could likely make the Boot Camp engineers' lives a lot easier, and while I know less about virtualization software like Parallels Desktop and VMware Fusion, they might be able to sleep better at night as well. Ultimately, if EFI support in Vista makes it easier for Apple to support running Windows on a Mac, this could likely yield even more sales from swtichers - especially those who need Vista for things like work or gaming. As to speculation on whether this could bring some of the wilder stuff like running Windows apps in Mac OS X without the need for the Windows OS or virtualization tools, I'll leave that to the tin foil hat enthusiasts in the audience.
Microsoft Windows Vista
Microsoft Windows XP